Ok, so I'm still trying to figure out what this noise/vibration is so here are some details:
It is an rpm specific noise/vibration that starts around 1,800 rpm or so and goes thru about 2,200 rpm. Under full-throttle or load it is not there, but gets worse the lighter the load is and is the worse when just cruising and maintaining speed. I cannot feel it when idleing, only when driving. The noise that goes with it sort of a low growl sound, but not like grinding or anything. When cruising or maintaining speed, the vibration turns into a rythmic vibration that kinda goes off and on for about a second each. On for a second, then off for a second... This seems to very slowly be getting worse over time, so I hope to fix it before major damage occurs! The car has a 355 SBC, 700r4 tranny, 8.5" posi rearend.

Some things I have done over the the past 6 months: Rotated and balanced tires even tho I don't think it is realted to tires/wheels. I balanced te driveshaft again and installed new u-joints and corrected pinion angle to be about 0 degrees now.
So I'm still trying to determine if it's in the motor or tranny? Could it possibly be an accessory? Anybody got a clue?

Thanks for any and all suggestions.

Bill C.


------------------
Bill C.
'71 SS (now with 467BBC)
'70 Nova 350/700r4
ACES #2780
Colo Spgs, CO

Are you SURE this is RPM related, and not MPH?

It doesn't vibrate while parked
It is not the motor.

It is load sensative
Likely directly related to rear suspension and the changes that occur their.

You say you check the pinion angle. Perhaps you have done this with some error?
Two scenrios to consider:

1.) when I bought my car, the rear was lifted with larger springs. This caused a downword pinion angle. Noise was oinly present during braking. During acceleration the angle got BETTER (upward during squatting).

2.) Club members car got ahold of some shorter upper control arms. An eye-let to eye-let measurement yeilded only a 1/4" difference, but was enough to cause the same as #.1) .

Have you check out your tranny tail-shaft bushing that goes to the crossmember?



------------------
71' 3880# with me. Big Block 402, Merlin oval heads, 10.2:1CR, TH400, 3.73 posi,
1/8th: 8.0 @ 88mph
1/4: 12.5 @109mph w/ 1.89 sixty foot (street tires)
Picture of me roasting the tires and other guy stuff (http://www.auburnextremeracing.com/drivers/mike/)
My other site, picture oriented (http://www.chevelle-ss.com/Member's_Pages/Mike_S.htm)

-Heart of Dixie Chevelle Club www.chevelle-ss.com (http://www.chevelle-ss.com)

Try what I have done to isolate my vibration.
Jack up car using rear axle and front A arms as jack stand points(that way car is sitting as it does on the road).
Have a friend help out by sitting in the driver seat and operating controls.
Get rear wheels up to speed & stand behind car and watch the rear wheels. Remove wheels & see if vibration is still present. if yes,
remove wheels and brake drums and run at speed.DO NOT USE BRAKES DURING THAT PROCEEDURE,LET THE AXLES COAST DOWN TO A STOP BY SLIPPING TRANS INTO NEUTRAL
If you still have vibration its somewhere besides wheel assy.
Remove drive shaft check again(isolating rear end)
Unbolt Torque converter slide it back towards trans then run engine(isolating trans)
Hope this give you a place to start.
BTW what brand tires you running

------------------
Philip Mullaly
72 TPI El Camino
You can never fix a Ford,You can only work on them alot.
70 442 (http://www.chevelles.com/showroom/442lftsd.jpg)
The Z-meano (http://www.chevelles.com/showroom/Caminoside.jpg)
Cowl induction injection (http://www.chevelles.com/showroom/tpienglft.jpg)

Bill,

i read something on a F-Body site regarding Hydramatic 4L60 and 700R4 trannies. The mentioned vibration/noise occurs on low rpm either without load, or in the reverse gear. Problem: The pressure regulation valve starts swinging. Solution: A new one should fix it. Partnumber 8684048.
I don't know if this is your problem, but it might be worth checking out.

Olli


------------------
[O]==+==[O]
Team Member #1920
71 2-door Chevelle Malibu (http://www.donmega.de)

"You can't impregnate me with all your foreign words!!"

Check your axles. I had a similar problem, and it turned out to be the axles. The bearing surfaces were pitted and worn out. New axles fixed it.

------------------
Mike Newby

69 Chevelle 355/TH200-4R
97 Grand Prix GTP
64 Chevy C10 Pickup
79 Suzuki GS550

BC,

I have the exact same problem and have narrowed it down to the tranny / torque converter.

I have too many projects going right now to tear my rod down, but I am going to replace the torque converter and have the tranny checked out when the time comes.

Thanks Bill

I didn't read far enough to see if anyone mentioned this yet, but have you checked your u-joint on the driveshaft? I had a similar problem with a rotational vibration, i kept looking for it and couldn't find it. One day i was under the car and noticed the u-joints and how they looked a little dry. Took out the driveshaft and checked it out, they were totally gone. Just another idea to check out.

Daniel

i have a '62 nova that had the same problem...

i replaced motor mounts and tranny mount

i did a lot of work on front and rear suspension ... and the problem persisted...

i replaced the harmonic balancer and nothing... last thing i changed was the fly wheel...

i wish i would have started there... i got a used fly wheel from the junk yard for $10 and replaced it myself... i would have saved a lot of money...

it turns out i had a balanced fly wheel... i needed an unbalanced fly wheel.... don't know if it is the same problem on your car... but... it sure sounds a lot like the issue i had...

anyway... i hope this helps...

My turn.... I guess axle bearing. Happened to my K5 Blazer. Couldn't figure out what it was. Very strange noise, sounded like wire rope being pulled around a sharp corner, if you know what that sounds like. http://www.chevelles.com/forum/biggrin.gif

Later
Steve

------------------
66 327 Malibu (Written off Sept 1 2002 Hopefully can save)
80 Malibu Wagon(summer 2002)
"Rice Eating Pony Killer"

Just another shot in the dark, but my trans dipstick was hitting the firewall and making a heck of a floor vibration at certain RPMs. A spliced in heater hose solved it. Next time the motor comes out, I'm beating the firewall with a BFH.

Another stab in the dark: check engine (or trans) mounts....

Olli,

I would like to check out your suggestion, sounds very possible. I have my problem narrowed down to the tranny or torque converter which I have also been told can cause this symtem. Do you have any idea where I could find that link? How hard is it to change the pressure regulator? I only know enough about the inside of trannies to be dangerous.

Thanks Bill

Here's my guess: I can't remember if the 700R4 has a tailshaft bushing or actual bearing, but if it's like the 4L60-E it might. If so, check it for wear. Simple, cheap part and it helped my vibration in my '94 Impala SS (didn't eliminate though).

Good Luck!

------------------
Alan Ray
1971 Chevelle (http://www.chevelles.com/showroom/desertvelle71.jpg) 350ci 258rwhp @4900/326rwtq@3250
Got 9-inches? (http://www.chevelles.com/showroom/nineinch.jpg)
1994 Impala SS (http://www.chevelles.com/showroom/alimpala3.jpg)

Wow, thanks guys... definitely got me some new things to try, and some to not try! Here's some answers and some more info on my troubleshooting... first, I have poly bushings for both motor and tranny, so doubt they are worn! But will check them for looseness! I also had it in a rearend shop where I know the owner recently and he concluded that it was not in the rear end... and from the fact that it is rpm related, not speed, that does make sense. Otherwise, it would happen at different rpms depending on what gear it was in and would then be more speed related where it would occur at particular speeds. Also, the rearend was rebuilt last summer and everything looked great then and all new bearings installed, so again, I don't think rearend.

BBBmike, have triple checked the pinion and to answer others, the driveshaft was just balanced and new u-joints put in for good measure. No change after that either.

Phil, I have tried that, but the vibrations are very faint and hard to feel/hear when there is no load on the system and the wheels spin freely. I'm running BFG TAs' 235/60s all around.

Olli,
That idea definitely has merit... My next plan to was take it to a tranny shop and have them service/look at it. I'll mention that to them. Any idea how hard that valve would be to replace?

66BBCONV,
Hope it's not the torque convertor, but have also resolved myself to it either being the motor getting out of balance or the front part of the tranny. I've also thought about the tranny pump... anyone have a clue if that could exhibit those kinds of symptoms if it is going bad?

Greg, I'll check for stuff hitting in the engine compartment... I have checked everything under the car and made a few 'modifications' where things were close!

66BBCONV,
Please let me know if you try the new valve and it does anything! Sure would help!

Thanks again to all the suggestions, keep 'em coming!

<BLOCKQUOTE>quote:</font><HR>Originally posted by 66BBCONV:
Olli,

I would like to check out your suggestion, sounds very possible. I have my problem narrowed down to the tranny or torque converter which I have also been told can cause this symtem. Do you have any idea where I could find that link? How hard is it to change the pressure regulator? I only know enough about the inside of trannies to be dangerous.

Thanks Bill<HR></BLOCKQUOTE>

Bill(s), http://www.chevelles.com/forum/smile.gif

I'm no tranny expert, I just remembered reading about that somewhere.
I haven't found any instructions on how to change the valve but you can search google for the given partnumber and you'll find a short description of the problem.

Bill (WI), do you know a place named Black Creek west of Green Bay? I used to have a pen pal there... Ahhh, she was so cute http://www.chevelles.com/forum/wink.gif

Laters!
Olli



------------------
[O]==+==[O]
Team Member #1920
71 2-door Chevelle Malibu (http://www.donmega.de)

"You can't impregnate me with all your foreign words!!"

Olli,

Yes, Black Creek is not too far from where I live. They have a bar/ restaurant with great food, Surf and Turf thing we like.

And yes the Wi girls are great.

Bill

Hi Bill
I had to change out the trannie bushing (rear) and just turn the drive shaft 180º, my light vibes @ 2200 rpm disapeared.

Jim

Shot in the dark #2: You said you balanced the wheels. Did you check the rim for trueness (eg a bent rim)? I have had a bad rim balance ok, but still vibe bad....change all 4 tires/rims and try it...?

Olli,
Thanks again for the part number, I'll definitely check into that!

Jim,
What do you mean by rear tranny bushing? I'm no tranny guy, that's for sure! I might try rotating the driveshaft 180 degrees... can't hurt right? And it's free!

Bow_Tied,
The rims are ok, nothing great... but balanced out and looked good on the spinner-thing. I don't think it is wheel realted because that would tend to be more realted to a specific MPH, not RPM. And I did rotate the tires when I have them balanced and there was no change.

Thanks again guys, got enough things to keep me busy this weekend, I'll let you know if I find anything.

Bill C.

Hi Bill
A bushing is on the tail shaft "end" and mine was worn out so it replaced to help out the bad vibe's problem. I could move the yoke up & down a great deal. Everything started when i had a -4.2º on the trannie slope and a -1.5º on the rear end. After many higher speeds on the freeway and 15K+ miles the vibration started. Now it's -1.8º trannie & -1.5º rear end and just turning the drive shaft 180º was the cream on top of it all (very smooth) now after 7K+ miles. Good luck. I Also put a new yoke in just in case the splines were worn.

Jim

[This message has been edited by Jim Elliott (edited 12-04-2002).]

[This message has been edited by Jim Elliott (edited 12-04-2002).]

Jim,
Thanks again, I'll definitely be checking that out!! You wouldn't happen to have a part number for that bushing do you? Sounds like it could be part of the problem as my drive shaft was pretty far out there on angle... got it shimmed up now to almost zero, but the damage may already be done! I've noticed my rear seal leaking on the tranny also... so that could explain that also!

Thanks again,
Bill C.

Hi Bill

I have NO part number on your trannie but some of the better parts houses will have both of the parts you need. Just how far in/out is your yoke ?? sometimes it can be in or out tooooo far and worn out also. Case in point is my trannie man's 65 rustang got a replacement 5 speed (O.D.) installed and it had a weird vibration, it was caused by the yoke bottoming against the case but he swore the trannies were the same size. Ya sure !!! we had to cut off 1 1/4 inch on the drive shaft. Good topic and everyone will benifit with all of the replys. Good luck

Jim

I just fixed a vibration in my SS caused by the driveshaft being 1.5" to short. I also had a constant seepage from the seal that has gone away.

------------------
Philip #42
1964 El Camino
1964 Malibu SS FOR SALE
1978 El Camino

Jim,
I gotta say, you definitely have sen your share of this stuff... turns out, the driveshaft was actually too long and driven that way for about 2 years! I just found this out while doing some work on the rear end and then couldn't get it back into position... kept hitting the driveshaft and bottoming out in the tranny! That's why I had the driveshaft shortened another 1" and re-balanced etc. Now the driveshaft fits like it should and doesn't bottom out! But the vibration is still there so I think maybe it already did damage to the rear bushings. Should there be any play in the rear output shaft of the tranny with driveshaft disconnected?

I'm going to try and get under there tonight or tomorrow so I'll let you guys know.

Thanks again,
Bill C.

64ElCamino, You are one lucky dude with a driveshaft that was that short didn't cause more than a vibration. Glad you caught it!

Hi With a car sitting a rest on the ground how much transmission yoke should you see between the rear of the transmission and the sholder of the yoke? I have about 1" showing on my car. Dave

Hi Bill

With the yoke inside the trannie you will have slight movement BUT not much, I have never tried to move the shaft with the yoke out Gotta try it next week tho. Glad (but sad) to see you found the cause now that whole area will need to be rebuilt "bushing & seal" and maybe a new yoke purchased cus of spline wear/damage. Off the top of my head a new yoke is around $65.00 but perhaps someone who has better knowledge of changing u-joints (bigger & better) will chime in with a suggestion. What the heck, for a few more $$ you can have a "new & stronger" u-joint assembly. Like i said once i got rid of my bad vibes (40-45 mph 2200 rpm) just by turning the drive shaft 180º trust me a dab of paint now matches up the reconnect marks.
Please keep all of us posted on your work/results and i wish you well.

Jim

DSR
Approx 1" hanging out will be ok providing the rear end has a -2.0 angle and same on the trannie drop. A stock leaf spring setup will let the rear end jump all over the place which can/will wreak havoc depending on the amount of applied power in conjunction with drive shaft length. Good luck

Jim

I had the same problem years ago, but initially had rear seal leaking on tranny. It was an older truck, and was just trying to make it a little more roadworthy. replaced the seal, and the thing kept leaking. Talked to a old tranny guy and he gave me a new bushing to put in it. Come to find out, the driveshaft yoke was ground on pretty good from the fit being bad for a while. Picked up a new yoke and another seal, installed with a new bushing and that truck road like a Cadillac. Would never have thought of it making the thing vibrate (it was an old truck....). Inspect the yoke carefully, those bushings are bronze with a thin coating on them. If they are beat up some, they cant take it, and lose concentricity. they get sloppy under a load and de-accelerating causing a vibration. Good Luck!

Well. I pulled the driveshaft out today and I can wiggle the end of the tranny output shaft pretty good. It moves probably about an 1/8" to 3/16" most ways from center... I assume that is too much??!! I'll go ahead and replace the bushing if I can figure out how! Anyone care to throw in a few pointers about that??!! Do I just remove the tailshaft housing and it will be obvious? Thanks!

Also, I looked at the yoke and cannot see any signs of wear or damage... but what exactly do I need to look for? The outside looks perfect as I just polished it when I had it out not long ago. The splines look ok, but will I see obvious damage?

Thanks again all, let's hope this is it!

Bill C.

Bill, you can replace the bushing two ways: tailshaft on or off the tranny. If you pop the tailshaft seal off, you'll be able to see the bushing. The bushing needs to be pressed out and a new one pressed in. There's a tool for this (can't get to snap-on site to link). I pulled my tailshaft out and took it to a shop. For $20 they pressed the old bushing out, pressed new bushing and seal in. You can get the new bushing from any Chevy/GM dealer for ~$5. You also might want to pick up a new tailshaft to trans case seal (another $5). It's a pretty simple and cheap job.

------------------
Alan Ray
1971 Chevelle (http://www.chevelles.com/showroom/desertvelle71.jpg) 350ci 258rwhp @4900/326rwtq@3250
Got 9-inches? (http://www.chevelles.com/showroom/nineinch.jpg)
1994 Impala SS (http://www.chevelles.com/showroom/alimpala3.jpg)

Thanks Alan, I'll check into that! Sounds simply except for the pressing in/out part... think I'll just bring it to a shop and let them do it! Should be pretty cheap right?

I'll let you know how it turns out.

Bill C.

probably less than $20 Bill for the press work. I'm in inflated price central (S.F. Bay Area), so it may be cheaper out your way.

You might be able to rent the tool as well. Let us know how it turns out!

------------------
Alan Ray
1971 Chevelle (http://www.chevelles.com/showroom/desertvelle71.jpg) 350ci 258rwhp @4900/326rwtq@3250
Got 9-inches? (http://www.chevelles.com/showroom/nineinch.jpg)
1994 Impala SS (http://www.chevelles.com/showroom/alimpala3.jpg)

Jim Thanks for the reply Dave

Dave, your welcome

Bill i'm just checking your progress. I would like to see this ornery problem nailed.

Jim

UPDATE!

Ok, got the new bushing, rear and front seal put on the tail housing and got it installed back into the car last night. After getting everything hooked back up and running guess what?


No difference... http://www.chevelles.com/forum/frown.gif

The vibration is still there, just like it was before... no noticeable changes to it. I think my next trial is to bring to whole car into the tranny shop and see if they can determine anything. I need a tranny service anyways...

Guess it's back to the drawing board and to try some more stuff that was suggested. Not sure when I'll get to it tho, I got to go out of town this weekend...

Thanks for all the help so far guys, anyone still up for more guessing games?

Bill C.

Bummer Bill http://www.chevelles.com/forum/frown.gif You can rule that out now at least.

How about the flexplate? I've heard of people having bad flexplates contribute to vibrations. Is the tranny mount in good shape? Maybe it's time to try pmullaly's
suggestions at the beginning of this thread. I'm kind of out of ideas for you. Anyone else?

------------------
Alan Ray
1971 Chevelle (http://www.chevelles.com/showroom/desertvelle71.jpg) 350ci 258rwhp @4900/326rwtq@3250
Got 9-inches? (http://www.chevelles.com/showroom/nineinch.jpg)
1994 Impala SS (http://www.chevelles.com/showroom/alimpala3.jpg)

OK, one more idea and a free one at that.
Bill go to Inland Empire driveline web site http://www.iedls.com and check them drive shaft angles out. With a magnetic protractor measure every angle from the engine dampner ALL the way back to the rear end. Your car will hafta be on a level drive up rack for ease of measurements. Will stay tuned and good luck.

Jim


[This message has been edited by Jim Elliott (edited 12-12-2002).]

[This message has been edited by Jim Elliott (edited 12-12-2002).]

Bill,

Go talk to the tranny guys. Like I had said before look at the torque converter. From what I have been told this is a very common problem to have the torque converter give you this vibration.

Like you, I have checked everything else to eliminate other possibilities and it is still there. Not good news for either of us, if this is what it turns out to be. It will not be cheap like a u-joint or something.

And thanks for keeping us posted, hope you get it solved.

Thanks Bill

Thanks again guys...

Next week I'm going to drop it off at the tranny shop and see what they say. They will check it for free, but will probably just go ahead and get it serviced while I'm there. Since I'm out of town this weekend, I'll have to check back and post what they find next week.

Talk to you then!

Bill C.

Ok, time for another update!

Took the car to the tranny shop today and let them play with it most of the day... verdict?! Nothing wrong with the tranny! They actually said it looks quite good and the car is very well put together abeit a little tight in spots! I was pretty proud! They said the leak was going from the governor cover, not the tailshaft, so they popped it and put in another seal and also serviced the tranny. I was glad for the good news that it is not the tranny, but then the sad reality hit that the vibration is still there. The tranny guy didi say that the exhaust was pretty close to some floorboards and crossmembers in spots, so he suggested maybe the car was tweaking just enough to make it hit?? Does that sound reasonable? Still doesn't explain why it would be a rythmic vibration tho.

Bottom line is that it looks like we are narrowing down the problem to the motor end... don't know if that's good or bad. I did notice tonight that the distributor is pretty darn close to the firewall if not hitting the firewall... any way I can shim the tranny mount or anything to move that away slightly?

Thanks again,
Bill C.


------------------
Bill C.
'71 SS (now with 467BBC)
'70 Nova 350/700r4
ACES #2780
Colo Spgs, CO

Are you sure it's not your driveshaft or differential?

------------------
Mike Newby

69 Chevelle 355/TH200-4R
97 Grand Prix GTP
64 Chevy C10 Pickup
79 Suzuki GS550

Bill,

Seems like it's time to try some accessories:

Water pump is a possibility, either from the pump itself or the fan - if you're using a mechanical fan, try swapping fan blades. Not really sure how you could check the pump.

Have you tried your speedometer gear/cable?
Distributor?

Mike,
Can't guarantee it, but have checked those things already and they look good. If you read some of the prior posts, I've had the driveshaft out, shortened by 1", then rebalanced and new u-joints added. I even tried rotating it 180 degrees to see if there was any difference. no changes. I'm pretty sure it's coming from the front of the car, not the rear.

Xtreme,
that will be my next objective... to try and test some accessories. I'm thinking if I take the belt off the water pump, then that would test both the fan and the pump right? The fan is a flex fan, I don't really like it, but haven't found a 6 or 7 blade stock fan yet that will fit my shroud... need to get a new shroud! I don't know what other accessory it might be... I'm going to try and get the distributor away from the firewall a tad to make sure it is not rubbing... as soon as I figure out how!

Thanks again for all the suggestions.

Bill C.


------------------
Bill C.
'71 SS (now with 467BBC)
'70 Nova 350/700r4
ACES #2780
Colo Spgs, CO

Hi Bill
Plenty of ways to alter your engine angle to move the ignition away from the body. My favorite is to shim the frame rails cuz it's easier. Getting lazy in my old age i guess. Hope you have taken the time to REALLY look at the Inland empire driveline web site, It is loaded with tips with our problems. Have you leveled your car on all 4s and measured the engine angle with a good protractor yet ?
Thats the starting point and i prefer a -2º for starters. Good luck and happy hunting

Jim

Jim,
I haven't got that detailed quite yet... before I was going by the angle of the tranny versus the rearend... that's how most places show to do it. I have seen the Impire site you talked about... good info there! I hadn't really thought about shimming the motor tho... figured I'd do it at the tranny mount, but maybe engine would be better. Whe you say -2 degrees, is that slightly down in the rear/tranny side or front side? Another thing that came to mind after you mentioned motor mounts... the car was originally a 307 car and it took me several tried to get the right mount mounts to fit the frame mounts... could the frame mounts be different? I mean are the 307 and 350 frame mounts different?

Also, in thinking about it, I think the motor is already slghtly down in the rear or tranny side, so what would be the best way to bring it back up if needed? That's why I was thinking of shimming the tranny mount...

Thanks,
Bill C.

yes, the 307 and 350 mounts are different. You say you only get the noise when you are cruising? not when you are giving it gas? It is possible it could be the exhaust rattling. I know when I first start my car up the exhaust rattles against the rear valance. Have you checked the flywheel? it could be cracked, and you would only notice that when you are not giving it gas. sometimes they crack all around the bolt holes. I had that problem once, went nuts trying to find it and then I described it to a old mechanic, and he told me to check that, and thats what it was.

Hi Bill
Tireburner is correct in the difference in motor mounts. Since i always start at the engine balancer with a magnetic protractor i know from that point how far down the trannie angle is. The trannie cross member is what i shim at the frame "if needed" not the mount point. Shimming/changing the motor mounts would be a BIG PITA but sometimes it has to be done if a major angle problem creeps up. As much as possible i like the tail down at the trannie right at -2º measured as stated at the engine balancer cuz i just dont trust any point of measurement in or around the transmission. Hope you enjoyed the Inland empire web site especially "vibrations" with the 700 trannies installed VS engine speeds, quite interesting and correct. Hey Louie Hammel, are you out there ?? Join the fun cuz it's getting better by the day. We are going to get it right.

Jim

Update...
ok, So it's taken a while to get anything done over the holidays, but here is what I found out today. I was looking over the Inland Empire web site and they suggested using the starter mounting point or the starter case itself for a reference on the engine angle, so I tried using the starter case to find the angle. It measured about -5 degrees by that method. The rearend still measured about 3 1/2 degrees and the driveshaft itself is about -1 1/2 degrees. I thought the engine/tranny angle of -5 degrees might be a little much, so I put a couple of washers between the tranny crossmemer and the tranny mount. It got the engine angle to about -3 1/2 degrees or -4 degrees. I then took it for a test drive and things did seem to be a lot better, with much reduced noise and vibration. I'm not 100% sure it is curec and that it was coming from the driveline, but I'm leaning that way. I figure it might also be because the distributor may not be hitting the firewall and possibly something else like an exhaust pipe might not be hitting something now.

But I still have some more questions regarding the driveline angles and such. First, I think it was Jim who was talking about shimming the tranny and suggested shimming the crossmember points on the frame and not shimming the tranny mount itself... is there a reason for this? Will shimming at the tranny mount hurt anything? Sure is easier...
Next, by shimming the tranny, I am going to be changing the angle of the driveshaft right? Isn't this going to cause the driveshaft to increase in angle? If I get the engine angle to about -3 degrees, won't that increase the driveshaft angle to about -3 degrees so that now I would have an angle between the tranny and driveshaft of about -6 degrees?? Which would be bad right? I guess I've read/heard that the engine angle should be about -2 degrees and really, the only way I see to adjust this is by the tranny mount point. So if I get the engine angle correct at approx -2 degrees, then won't the driveshaft angle be excessive at the tranny ujoint? I know I can always add more shims to the rearend, but now I', worried about the tranny to driveshaft angle being too much.

Hope that makes sense?

Thanks,
Bill C.

Hi Bill

Shimming the trannie mount is good, I am just too lazy and old soooo i just jack up one side and insert the x-member shims then do the other side. Now on to the reference point, go ahead and measure from the starter BUT just to be sure lay your protractor on the engine balancer and see if they are the same. If the angle of the output trannie shaft isn't the same as your engine balancer your in a heap of trouble. I think it will pay you to go back to the Inland empire web site and re-read two items, (1) take the drive shaft out of the picture then look at the trannie/rear end angles. (2)On the site is why O/D trannies set up harmonics with weird vibrations. Since your rear sits at a -3.5 and you have moved your trannie to "approx" -4.0 from a -5.0 and a lot of vibes has disapeared i would venture a guess that another 1/2º (-3.5) at the trannie will give you a smooth ride. Stay warm and good luck cuz your close ! very close.

Jim

Jim,
Thanks again... the only problem with that and why I was having a hard time getting the engine angle is that it is virtually impossible for me to get a measurement off the balancer. The pulley is too large and the crossmember/sway bar are in the way. I'm going to try and get under there again tomorrow, so I'll try to shim just a hair more.

I know you said not to worry about the driveshaft angle, and I never really did until I read the Inland Emoire web site that shows how to account for this. I always figured if the tranny angle was down, then the rearend should be up that same amount.

If this is caused by the driveline being out of wack, could this be causing damage to the new ujoints?

Bill C.

Hi Bill
Yup !! If your drive line is really out of whack in time your joints will break. One of the guyz down here welded up his spring perches "wrong" and wound up with a -11.5 and wrong engine mounts also (-6.5 engine). He made 10 decent passes with it (12.10et) then some really good vibrations set in. Needless to say it was a trailord car "thank god" cuz he wouln't have made it home on the street. Go ahead when you have the time and jack up your trannie a dab more (1/2-1º) and you should be good to go.

Jim

Frequency Specific Complimentary System Resonance,,, I hate when that happens.
You guys are just having WAY too much fun with this vibration thing. You seem to be on the right track, I think you're only a little finessing away from being done.
Bill, JimElliot, everyone; Merry Christmas and Happy New Year. I've been doin' the holiday thing for a couple of weeks now and haven't been in here to see what's goin' on.
The vibration. Annoying little things, aren't they? I live about twenty miles down the freeway from Inland Driveline. They've built driveshafts for me before and I think they do good work. Their website is also good and describes the driveshaft angle phenomenon well.
Although it may seem subtle at first, the driveshaft and BOTH u-joint angles are critical. A u-joint operating at any angle other than zero will accelerate and decelerate the driven component SOME amount depending on the angle. In order to return the second driven component (the pinion yoke) to a constant rotational speed, the two u-joints should operate at the same, but opposite, angles. Our cars have springs in the suspension and, as such, will vary the angles of the u-joints depending on load, weight transfer, etc. Setting up the correct driveline angles is therefore only a 'compromise' of the position of the suspension system we anticipate using most often.
Ideally, the output shaft yoke and the pinion yoke should be parallel but not inline. Adjustments are made to either end to achieve a parallel arrangement. Once done, the driveshaft u-joint angles will be equal but opposite. This will eliminate any cycling vibrations induced by the driveline.
This is a heck of a lot easier to say than it is to do, there's a lot of little things that can bite ya' like cheap angle guages and accurate zero references.
And then there's,,, wait a second, (What?),
Ah well, gotta go, dinner's ready.

Talk to you guys later,

Louie

Hey Louis, good to hear from you again... it's been a while, hope all is well. I need to get back over to the Superflow shop and bug your buddy and see how to get my car on the dyno! Well, maybe someday!

Anyways, here is the latest! Last night I got back under the car and proceded to shim the tranny mount some more. I got it really close to about 3 1/2 to 4 degess down using the starter case as a reference. It took close to 1/2" worth of shims, but it is there! i took it for a spinn and things are definitely improving! The noise has all but disappeared and the vibration has been significantly reduced, but there is still a rythmic vibration around 2,200 rpms. It is not near as bad as before, but still there.

I have some more questions also. After I had shimmed the tranny some more, I took an angle reading of the driveshaft also... and it was right about -3 1/2 degress also... same as the angle I got off the motor! So I drew it out on paper and looked and saw it was possible that if I brought the engine agle up enough that the driveshaft would follow and eventually they would be equal! Looks like I'm at that point now! The rearend angle should not have changed right, So in theory that angle between the driveshaft and the rear pinion yoke should have lessened also right? that should help reduse vibrations and all right? But now it looks like I'm getting pretty close to having just a straight line from the tranny output shaft all the way to the rearend! I understand this is really not desireable?

Another issue I was looking at while under the car yesterday that I'm wondering if it is contributing to the problem... Right now, the car sits about 1 1/2" higher int he front than I like. This is because I had to put some stiffer springs in the front so the car would not rub the tires on the inside of the fender. The wheels I have need a little more offset to them to bring the tire in where it needs to be, then I will put the correct springs back in and drop it to where it should be. The question or observation is that it looks like the raied front end is causing the engine and such to be higher than normal, thus creating a higher approach angle to the rest of the drivetrain. It looks pretty obvious that this might effect the actual angle of the driveshaft in relation to the engine, right? Just trying to understand...

So basically, it looks like I'm done for now and will have to live with the slight vibration that is still there. once I can afford to get new rims, I'll correct the spring problem and hopefully drop the front end back to where I want it. Then I'm sure I'll have to go back thru and re-adjust the angles to get to where I need to be.

Any other suggestions?

Thanks again,
Bill C.

Hi Bill

Bill, Louis and everyone else one BIG happy new year to you all. Thank you Louis for writting it up a whole lot better than i have, I also enjoy the products and info from Inland empire and visits. One big DUH from me is not telling you Bill how to work around smallish areas on your harmonic balancer, what i do is clamp on a piece of angle 90º then lay the protractor on it. Bill people who lower the cars (rear only) sometimes wonder why vibrations crop so just maybe raising your front 1 1/2 just might have that same effect. Now for some better news, the person who had incorrectly welded his perches on has seen the light and got it fixed ! Now for a little trade in work i will finish his up (next week ~maybe~). Since i zip over to Fontana 2-3 times a month one of these days i hope to drop in and see you Louie. DONT STOP YET Bill

Jim

[This message has been edited by Jim Elliott (edited 12-31-2002).]

Heya' guys, glad to hear all is well.
Bill, you can simplify your measurements and calculations if you start by establishing the angle of the output shaft relative to level and then the angle of the pinion shaft relative to level. Then, using whichever end is easier to manipulate, make both ends the same angle. To check the driveshaft angle and verify if both ends are at equal (but opposite) angles, install the driveshaft and measure the end of the driveshaft cup 'flat' of the u-joint with it facing straight down (plumb, 6 o'clock) Do this at both ends and be sure to use the cups that are retained in the driveshaft, not the yoke. You use the ones in the yoke to determine the output shaft and pinion shaft angles.
A couple of suggestions and reminders:
Try to perform all measurements with the weight of the driver and other passengers in the most likely highest percentage of vehicle use. It can make a difference.
Changing the ride height of the front suspension doesn't change the output shaft to pinion shaft angle relationship. Changing the ride height of the rear suspension does.
If you unknowingly change the weight in the trunk by at least 50 to 80 pounds during all this adjustment stuff you will induce error and confusion into the angle calculations.
Try not to exceed 3 degrees at each end and stay away from zero at each end.

The fluid pressure pump issue with 700R's is not entirely out of the question. The inherent nature of the design of the variable volume sliding vane outer cavity can possibly lead to a rythmic vibration in the main pressure line of the pump's output pressure. It manifests itself as a rythmic buzzing or vibration at certain road/load conditions. If you change the position of the Throttle Valve (TV valve cable) adjustment a few ratchet positions at the throttle linkage you should notice a slight change in the amount of load required to produce the vibration. It won't go away, it will just change the rpm where it occurs slightly. Fixing that one involves removing the trans and having a shop address the problem.
My winter project involves rescuing a MOPAR 8.75" rearend from a '71 Chrysler station wagon and adaping it to the El Camino's four-link so I'll be going through a lot of what you're doing here right now.

Submitted sincerely and respectfully as only we gearheads understand,

Louie

Guys thanks again for the info, here's the latest update:

After driving it around for a day, I realized the vibration was still there... Seems to be worse about 2,200 rpms now. I think there may have been severla things going on at once... something making a vibration/noise that started about 1,800 rpms and something making a rythmic vibration at about 2,200 rpms. The first vibration/noise is now gone making me think it was something rubbing or hitting the underside and harmonicing (?) about then. I think this got fixied when I shimmed the tranny mount. The rythmic vibration at about 2,200 rpms is still there, but there is really no noise associated with it. I went back to taking the angle off the ujoints and yokes and lowered the amount of shims I had under the tranny mount about 1/8". Now the tranny output shaft/yoke and the diff yoke both look to maesure about 2 1/2 degrees. Unfortunately, it started to snow last night and is still snowing/blowing around, so I won't be able to drive the car for another day or two. My suspicion is that the vibration will still be there... reason being is that I really think Louis is right and that it is the tranny fluid pump. One reason I suspect this is that while I was driving yesterday, I could change the rythmn of the vibration by moving the gas pedal/TV cable position and not changing anything else. With the RPMs and speed remaining constant, the rythmn could be slowed or increased. Once I get to drive the car again, I want to try Louis' theory of changing the position of the TV cable on the carb end and see if that changes the RPM of the vibration.

Guess I'll keep you updated when I get more info.

Thanks Again,
Bill C.

<BLOCKQUOTE>quote:</font><HR>Originally posted by LouieHammel:
Heya' guys, glad to hear all is well.
Bill, you can simplify your measurements and calculations if you start by establishing the angle of the output shaft relative to level and then the angle of the pinion shaft relative to level. Then, using whichever end is easier to manipulate, make both ends the same angle. To check the driveshaft angle and verify if both ends are at equal (but opposite) angles, install the driveshaft and measure the end of the driveshaft cup 'flat' of the u-joint with it facing straight down (plumb, 6 o'clock) Do this at both ends and be sure to use the cups that are retained in the driveshaft, not the yoke. You use the ones in the yoke to determine the output shaft and pinion shaft angles.
A couple of suggestions and reminders:
Try to perform all measurements with the weight of the driver and other passengers in the most likely highest percentage of vehicle use. It can make a difference.
Changing the ride height of the front suspension doesn't change the output shaft to pinion shaft angle relationship. Changing the ride height of the rear suspension does.
If you unknowingly change the weight in the trunk by at least 50 to 80 pounds during all this adjustment stuff you will induce error and confusion into the angle calculations.
Try not to exceed 3 degrees at each end and stay away from zero at each end.

The fluid pressure pump issue with 700R's is not entirely out of the question. The inherent nature of the design of the variable volume sliding vane outer cavity can possibly lead to a rythmic vibration in the main pressure line of the pump's output pressure. It manifests itself as a rythmic buzzing or vibration at certain road/load conditions. If you change the position of the Throttle Valve (TV valve cable) adjustment a few ratchet positions at the throttle linkage you should notice a slight change in the amount of load required to produce the vibration. It won't go away, it will just change the rpm where it occurs slightly. Fixing that one involves removing the trans and having a shop address the problem.
My winter project involves rescuing a MOPAR 8.75" rearend from a '71 Chrysler station wagon and adaping it to the El Camino's four-link so I'll be going through a lot of what you're doing here right now.

Submitted sincerely and respectfully as only we gearheads understand,

Louie<HR></BLOCKQUOTE>

Hi Bill, I to have the same problem with my 69SS but with a muncie.Replaced driveline,u joints,tail shaft housing bushing,seal,rebuilt the transmission.Now I'm replacing the vibration dampner,new front wheel hub assemblies including spindles.I'll be road testing this part next week, and let you know.Randy

BC,
didn't you take the transmission tec for a ride to hear the noise or feel the vibration at cruising speed? Did you ask him if they took it for a 60mph spin for a few miles. How could they say its not in the tranny? How did they come to that conclusion?

Team Member #74

In one of my 700R4 manuals it says that if the o-ring seal on the trans filter gets cut during installation it will cause chatter and/or vibration.

I'm about to change my fluid and filter to see if the chatter in mine goes away.

------------------
My Web Site (http://www.landry-family.com) (updated 01-04-03)

"Long Live Freedom!"

Chad Landry
TC Member #643
ACES Member #4556
'68 El Camino

65Camino,
Yes, he heard and felt the noise/vibration... told me it wasn't the transmission, but porbably just some harmonic caused by the poly bushings in everything. They did a service and pulled the pan, but said there was nothing in there to indicate a problem. One thing I noticed is that when I took some shims out this last go 'round, the noise is back and is pretty noticable at about 1,800 rpms. I think maybe the tranny is getting pushed against something maybe? I can't believe that removing 1/8" of shims would cause something so drastic to change!

I found out this past weekend that a friend of my wife's husband manages a tranny shop here in town, so I think I'm going to take it too him to get a second opinion on the tranny. The last shop didn't seem to know anything about a pump problem... anyone know if this is documented by GM somewhere?

Chad, Let me know if that changes anything... doubt it's my problem tho as the tranny shop just serviced my tranny with new filter and doubt if the before and after filters would both be cut!

Thanks again,
Bill C.