[JIM]

I have always had a small vibration somewhere in my drivetrain for as long as I have had this car (21 years). I recently removed the Muncie and installed a Tremec 5-speed. I have just recently drove the thing on the highway and anything over 70MPH will produce a tremendous teeth rattling, floor pounding, mirror blurring vibration. I was checking driveline angles with my inclinometer this past weekend. This is what I had:
Trans pointing down 3.5 degrees
Driveshaft pointing down 1.25 degrees (trans to driveshaft angle = 3.5 - 1.25 = 2.25 degrees)
Pinion pointing down 2.2 degrees (driveshaft to pinion angle = 2.2 + 1.25 = 3.45 degrees)
Driving the car with these setting was unbearable and I was waiting for something to let loose.
I raised the tail of the trans about 1" and measured again. I now have
Trans pointing down 2.7 degrees
Driveshaft pointing down 2 degrees (trans to driveshaft angle = 2.7 - 2.0 = 0.7 degrees)
Pinion still at 2.2 down (driveshaft to pinion = 2.2 + 2.0 = 4.2 degrees)
Raising the tailshaft did 2 things, lessened the angle at the trans by about 1.5 degree and increased the angle at the pinion by almost 1 degree.
So which change made it better????

The severe vibration is gone for the most part, but there is still something wrong there that vibrates the rearview mirror to the point where all cars are a blurred-double vision. I have read so many conflicting posts on driveline angle. I would like to hear some measurements from those who have installed a Tremec and know their 3 angles.

 

[AMBUSH904]

ok, here it goes. I had the same problem, had the rearend checked, the clucth and flywheel changed, replaced the driveshaft and joints,went with new set of wheels and tires, still no fix. Went to old performance shop in town, told the old fart behing the counter what was going on and how much I changed and everything we tried, He smiled and handed me a new set of pulleys for the block, And I guess the look I gave him said alot, because he said if it didn;t fix it to bring them back and he would give full refund. So waht the #&@$%, I tried it and yes the vibration is gone. Go figure.
www.camaromuscle.com

 

[ss3964spd]

Jim,

I chased a vibration problem for a long time and did a lot of reading on drive line angles in the process. From my basic understanding, and assuming your DS is correctly balanced....

Don't bother with finding the angle of the DS, the only angles to consider are those of the trans output and the pinion.

Idealy, one would want the angle of the output to completely off set the angle of the pinion. If you were to draw a straight line threw the center line of the output - extending rearward, then draw another straight line threw the pinion center line extending forward, those two lines should be paralelle - never crossing. Or, if the output is down 2.5, the pinion would be up 2.5.

Problem is one needs to account for the fact that the pinion will climb the ring - wrap up. Depending on how compliant the rear suspension bushings are, and how you drive the car, will determine how much you have to change the pinion angle to compensate for the wrap up. Think I recall reading someplace that 1 degree should do it. Braking forces will try to spin the housing the other way.

Therefore, if the trans is pointing down 2.5 degrees (from level), you'd want to have the pinion pointing up 1.5 degrees (from level). Of course, the actual angles will be determined by the ride height in the rear - meaning, the closer the center line of the trans is to the center line of the pinion, the less drive line angle there will be.

Dan

 

[JIM]

Ambush, my pulleys are new March pulleys and did not cause me a vibration prior to the tranny swap.


Dan,
As far as the direction of the pinion, I was told that it should never be pointed up. So I am confused on that one.

 

[ss3964spd]

Jim,

I haven't gone back and read the information for a while but I don't think a statement such as "should never point up" is correct.

Again, from what I recall, the ultimate goal is to have the pinion centerline perfectly paralelle to that of the trans output throughout the rear suspension travel - excluding the point at which it is inline with the trans output.

Let me ask this way. If you're sitting in your lawn chair, facing the drivers door, currently your trans output is pointing towards the floor and the pinion is also pointing towards the floor?

Dan

 

[ehjorten]

You now have about 5° of mis-alignment in your driveshaft (2.7° down at tailshaft and 2.2° down at pinion...2.7+2.2=4.9). This will definitely cause a vibration. You need to have your pinion pointing up, or at the least have it set level. As Dan stated, ideally the pinion would point up the same angle as the tailshaft pointed down given that there was no compliance in the suspension. Keeping the pinion slightly off by about a degree from the tailshaft will allow for some wrap-up in the suspension. Also...I would put the tailshaft back down some because u-joints don't like to run flat. A u-joint needs some angle to keep the needle bearings rotating.

 

[JIM]

Jim,....
Let me ask this way. If you're sitting in your lawn chair, facing the drivers door, currently your trans output is pointing towards the floor and the pinion is also pointing towards the floor?

Dan

Yes that is correct. Like a real shallow "V".
I spoke with Armando from Inland Empire Driveline today (I think Jeff @ Classic Chevy had him call me :thumbsup: ) and he said the same thing......my pinion needs to be pointed up to cancel. The only way I can do that is with adjustable uppers, so I will try them. I wanted to get them anyway to dial in the back end, but never thought I would need them to point the pinion up.
What confuses me is why didn't I have this severe problem with the Muncie? My pinion angle has not changed????
Thanks for the input guys and taking the time to read my brutally long post filled with math problems. I would sure like to see some measurements from others with stick cars.

 

[ss3964spd]

Got me Jim, maybe the vibrations produced by the Muncie simply cancelled the vibs from the mis-matched angles. .

I am math challenged so when I was reading up on the drive line angle information it really helped when when I saw drawing of what they were trying to explain via numbers. The paralelle line drawing did the trick for me - from there it all made sense.

If I get some time this evening I'll slide under the Impala and take some readings.

Dan

 

[JIM]

If I get some time this evening I'll slide under the Impala and take some readings.

Dan

Thank you

 

[JIM]

ttt for Dan.......did you ever get a chance to check the angles?

 

[sinned]

What confuses me is why didn't I have this severe problem with the Muncie? My pinion angle has not changed????

The difference is that the TKO is much longer than the Muncie, it is also much taller. When you installed the transmission it was nesessary to drop it's height for floor clearance (I've been there, I know). Also because the transmission is longer the angles change quite a bit. When I did my install the trans was at about 6* down and pinion was 3* up, I had a terrible vibration as a direct result of the swap. I cut a hole in the floor to make room (see here ) and moved the transmission up. I know have 4*, still not great but good enough eliminate most of the vibration. See thread here

 

[JIM]

Thanks for the reply. When I installed the Tremec a couple of months ago, I did do tunnel surgery. I measured my Muncie angle, wrote it down and then made sure I put the Tremec at that angle when I installed it. I have off from work on Tuesday. I am going to try a couple of different rear angles and take it out on the highway for testing.

 

[ss3964spd]

Have ya had a chance to chase this down yet Jim?

Dan

 

[JIM]

Unfortunatley no. I had to have a little surgery and have stitches in my right shoulder blade. That makes lying down under the car a PITA for now. Stitches come out later this week and I'll get back under there. Haven't driven the car in a week.

 

[Guest]

You are about 175 miles from me, not just around the corner. But, I could drive up if you get stuck or just need another set of eyeballs.

 

[JIM]

You are about 175 miles from me, not just around the corner. But, I could drive up if you get stuck or just need another set of eyeballs.

Wow, hey thanks for the generous offer! I'll keep that in mind.

 

[Guest]

Wow, hey thanks for the generous offer! I'll keep that in mind.

Are you going to the MCC meet in Northeast MD? I plan on going and making a pest of myself about transmisions.

 

[Jerry Briggs]

Jim, put the TKO 600 in my 67 and had no vibration problems until I installed the anti-hop bars to help control wheel hop. They raised the pivot point for the upper control arms higher and worked great. At that point the angles were to far off. Cured the problem with adjustable upper control arms. That let me adjust for the best angles. No more vibes at 65 and above now.

 

[JIM]

Re: TKO-600 users, I need some help (UPDATE)

OK, stitches removed from shoulder, crawled under car to work on pinion angle stuff.
First issue.....There was a burr on my brand new Mark Williams 1350 yoke and it was not letting the u-joint sit in it properley on one side. I fixed that, left my pinion angle alone and drove the car. BINGO! Big obnoxious, floor pounding, butt smacking vibration is gone. I still had the small vibe though, so I adjusted my new Edelbrock uppers to point my pinion up a little so it would be close to "equal but opposite" of the trans angle. This seemed to help a bit. There is still possibly something there, but hard to tell because I think I am really looking for it now. But I took it up to about 80MPH for a short bit and it seemed OK. A little vibe in the rear mirror and shifter handle, but nothing annoying. I drove it up and down route 33 here a few times. Had to stop for gas also. :sad:
But I think I will leave it alone for now.

 

[chev-hell]

ok, now im confused,all this crap just to install a tko (but i'm going to do it anyway ) someone draw me a picture of good vs bad pinion angle please!!!