I have a 69 chevelle SS 396,muncie 4speed. The motor,front end, trans,clutch,pressure plate throw out bearing,rearend,has all been rebuilt. This vibration comes in around 3000rpm, which vibrates through the shifter and the rear view mirror is impossible to see through. I don't know where to go next,been chasing this problem for years??? Anyone have any ideas???

are all the body mounts intact and in good shape (as well as the crossmember)

The body bushings have all been replaced within 5 years,motor mounts,and the driveline has been balanced several times.

What trans mount did you use?

I 'am using the stock crossmember with the square rubber mount that goes between the crossmember and the trans.

when you redid the clutch, you replaced the pilot bushing as well I assume?

Yes, I used a new bronze pilot bushing

I know in the old parts book there used to be two mounts listed. One for manual and another for automatic. Now they all list the one for both.
The only place Ihave seen as of late that has two different part numbers for the mounts is The Parts Place!
I have seen aticles where the use of the automatic mount can cause vibrations. This is the same problem peple have with the Energy Poly mounts because they are too tall! According to the tech I talked to at Energy the mount they sell is the same dimension as the automatic mount!

When I replaced the original mount I did compare it with a new mount,width, height, and mounting holes and it is made of black bubber.

3k RPM while driving or even in neutral?
Did it vibrate before you made all the changes?

If it is while driving, torque your lugnuts all the way around the car, if you can swap rims and tires, check and grease universal joints, etc.

Check to see that your exhaust is not rubbing anywhere and that the hangers have a rubber isolator.

Yes, it's while driving, I've double checked all lug nuts, and u Joints are greased. I guess I could try some different wheels though. I have headers with no rubber at the hangers for the exhaust.

Have you checked to see if your drive shaft is balanced. Had a vibration problem with mine and took the drive shaft and had it balanced and no more problem! Worth a try.

Yes, I've had the driveshaft balanced several times with no change in the vibration

Maybe it's simply a wheel balance issue. I'd take it to a tire shop to make sure a wheel weight didn't fall off and to get a closer look at the tires themselves.

Sounds like that's where I'l start with the tires/wheels. I'll let you guys know what the results are. I know in the past I heard from someone that if the inside mirror was blurry while driving it pertained to item on the car. And if the outside mirror was blurry it meant something else. Any ideas?

I'd start with wheels and tires.. First would be to torque the lugnuts to the same ft lb on all wheels (could be the simplest fix) look for cupping/scalloping on tires.

Make sure all wheel castle nuts are tightened and cotter pinned. Jack car and shake the wheel, if it is loose you'll know thats your issue, change bearings and seals.

Check universal joints (or change em they are cheap)

Check and make sure tierod ends are tight, and adjuster sleeves not loose.

Check upper and lower arm bushings and cross shaft for tightness.

Finally have wheels balanced and trued.

Check alignment.

Personally it sounds like something in the front end, a wheel issue, tire issue, loose lugnuts, improper lugnuts or wheel castle nut/bearings.

I had the front end aligned,new cross link, new upper and lower A Frame bushings. Wheels are torqued, but I do have a wheel lock on each wheel that is larger and maybe a little heavier than the rest of the stock lug nuts

To properly diagnose you need to isolate alittle more.Does this vibration go away if engine is put under load or put into neutral?Can you feel it in the steering wheel,seat of pants or feet?Does is change if you unload one side of car,like turning from left to right quickly?Front or rear,left or right?If you feel its tires and can determine possibly which one then swap it to the opposite corner,l/f to r/r ect..,and see if the vibration follows the swap.Its hard to just give a specific answer to a generic vibration as there are many variables and it could get costly and time consuming chasing every possible cause without some more info.

Thanks Scott, I'll try and switch tires/wheels. I believe it mostly vibrates in gear under load more than in nuetral. But, it still vibrates not as much at 60mph in nuetral.

trans tail shaft?

When you are saying trans tail shaft ,are you meaning the rear yoke on the trans?

Food for thought. Not saying this is your problem. http://www.camaros.org/bellhousings.shtml

Raven 1, Thanks for the website article. I've never considered the alignment a possibility. Would the vibration occur in early RPM up to high RPM? because mine only occurs at around 2500-3000 rpm??

Raven 1, Thanks for the website article. I've never considered the alignment a possibility. Would the vibration occur in early RPM up to high RPM? because mine only occurs at around 2500-3000 rpm??

Can't help you, never had a vibration problem. Thanks, I will now with the next car.

trans tail shaft?


I had exactly the same vibration, and I fixed mine by replacing bushing in the tail shaft. Look at your yoke and see what looks like excessive wear.

This bushing can be removed and replaced without removing the transmission.

Rocky

Really reaching here: A spring on your clutch disc is bad?

I know you said you balanced the engine and flywheel. Most pressure plates come balanced from the manufacturer, but somebody might have had a bad day at the plant. Have also seen the heavy side of the flywheel get lined up with the weights on the pressure plate, it would shake the teeth out of your head at 60 mph. Marked the pressure plate and flywheel, then loosened the pressure plate and moved it 180 degrees. Vibration went away. I also agree about inspecting the tail shaft bushing, also inspect the yoke and make sure it does not have excessive wear on the outside of the yoke. Thomas

Rocky, I replaced that bushing about 5 years ago and the same vibration still existed. But, I will take a look at it again maybe, it will show some wear,also had the yoke replaced at the same time. I will also, try and switch the pressure plate 180 degrees. Would anyone think that the tail shaft could be bent?. Has anyone had a problem with the bell housing not being centered that would cause this vibration?

Rocky, I replaced that bushing about 5 years ago and the same vibration still existed. But, I will take a look at it again maybe, it will show some wear,also had the yoke replaced at the same time. I will also, try and switch the pressure plate 180 degrees. Would anyone think that the tail shaft could be bent?. Has anyone had a problem with the bell housing not being centered that would cause this vibration?


IF you have done that, and gone the route of balancing drive shaft, tires and wheels, I think I would start looking at your pressure plate and clutch.

If your going to have to drop it again, I would either replace the pressure plate and clutch, your looking at $200.00 or take your flywheel and pressure plate and have the machine shop check it for balance as a unit.


Rocky

Is it a constant vibration or does it pulse?

I throw this in.... Is the driveshaft the proper length? I had a similar problem, Someone during the time it changed owners put a different shaft in and it was too short.. It was "Whipping" Not far enough on the tailshaft. I'm assuming the pinion angle is correct?

what kind of wheels? i had a weird rhythmic vibration in my Monte that would come on at about 60 and go away at 70. never really figured it out.
then one day i had the back of the car jacked up for some reason, and i gave the left rear tire a spin. i noticed it was a little bit off center. i verified this by setting a jackstand next to the car with a piece of wire slicking out as a pointer that pointed at the bead. when i spun the wheel, it had about 1/8" of wobble.
i loosened up the lugnuts, centered the wheel by sighting the center hub on the axle with the hole in the wheel, and snugged the nuts. i kept doing this and spinning the wheel until it ran true, then i let the car down and tightened the nuts.
when i went for a drive, it was silky smooth all the way up to 80mph.
the moral of this story: old school unilug wheels suck, and you should always run a wheel that centers off the hub.

I had exactly the same vibration, and I fixed mine by replacing bushing in the tail shaft. Look at your yoke and see what looks like excessive wear.

This bushing can be removed and replaced without removing the transmission.

Rocky

bingo :thumbsup:

Rocky, Have you ever been concerned with the position of the bell housing as when your stabbing the tranny in?. I used a pilot shaft to line everything up but, this time it was a little more difficult getting the tranny to go all the way through without a little persuasion. Could this be the reason maybe for a little out of line,which could cause the vibration?

Rocky, Have you ever been concerned with the position of the bell housing as when your stabbing the tranny in?. I used a pilot shaft to line everything up but, this time it was a little more difficult getting the tranny to go all the way through without a little persuasion. Could this be the reason maybe for a little out of line,which could cause the vibration?


I haven't had that problem. The bell housing is in place with dowel pins so that was never an issue with me. I had my tyranny out two weeks ago to replace clutch fork and throw out bearing.

When stabbing the tranny back in, I took 3.5 " shoulder bolts and cut the head off, and ground a screw driver slot in the end for easy removal after the tranny is installed.

By doing that i have four guide pins that let me slide the tranny in place with minimum force as the guide pins are long enoughto keep everything in line.

With that said, the only issue would be if the spline isn't completely in line and should just slide in with a little wiggle.

Are you sure you had your clutch plate in straight, even with an alignment tool just a little off, and that would take a little more effort to get the input shaft into the pilot.

If haveing gone the balance route with everything, Depending on if you wanted to spend the money, I probably would buy a new clutch, and have the flywheel checked for run out and balance at the same time.


Rocky

Rocky, Just put the car up on stands,started the car,in 1st gear and watched the tires turn. They look good from the side, but when you campare the bottom of the tread to the floor it looks as if the tires are uneven,hopping, or just not true. Randy

when you did the rearend, did you install new outeraxel bearings, check to see if you have any wheel play, I'm going through this right now! My Car started vibrating at any speed, seams this was the problem,

In your original post you said the vibration comes in at 3000rpm, is it just rpm, or does this happen at a particular speed.

Does it happen in any gear just at 3000rpm? or do you notice it at a particular speed. I'm trying to narrow it down to an rpm issue ( clutch, Flywheel,) or speed issue (Tires, Wheels,) and does the vibration go away?

On of the easiest things to check is take tires and wheels and have balanced, That way while tire and wheel is on machine, you can check to see if you have a bent, or out of round wheel. It doesn't take much out of round to create a vibration. You mention tires look uneven, (hopping) it is very possible you have a tire with broken belts. You might try a different set tires and wheels.


Rocky

If the vibration is lowered in neutral it is probably not tires/wheels.A slipped belt in a tire will have a constant vibration regardless of neutral/drive status.If you feel you have a faulty wheel /tire assembly then you should always roadforce balance it.Roadforce turns the tire on a force loaded drum and checks for out of round conditions that a regular balancer does not.You can also check the wheel and in some cases perform what is refered to as book matching.You mark the tire and wheel where the machine instructs,and line then the marks up.Minor roadforce conditions can be tuned away with the procedure but not major.A tire with a slipped belt is unsafe and should always be replaced anyway.Sometimes a tire will flatspot from sitting and the flatspot can be driven out.60mph for a while usually does it,sometimes putting 40 psi in temp.

With the old motor in the car it had a oscillating vibration at the same rpm,whether in or out of gear around 3000rpm and of course the noise/vibration would increase with more speed which meant you had to hold on to the shifter to quiet the vibration coming up through the handle. The rear-end has been rebuilt with new bearings and axles. I put in a new rebuilt motor,new vibration dampner,clutch,pressure plate, throw-out bearing,and pilot bearing. I don't drive the car very much, so it does sit for 6-7 months without driving,so maybe along with everything else, tires might have a flat spot.

I know you said you checked the Drive Shaft, but did you check the U-joints.If the U-joints look ok and you greased them,does not mean they are ok.It only takes one cap to have a bad bearing inside to foul the rest and now you have a bad joint.It may look fine on the outside.
Does the vibration go away if you let off the gas and coast,but come back when you give it gas again.Bad U-joint.I chased a problem just like this only to find out that one cap, and of course it was not the easy one to check was bad,never got any grease.Car ran fine for long enough to go out of warranty and then boom.Check it out.

rdshotss, You have been given a lot of great advise here and all might work. The one thing nobody has said is the rear pinion yoke. I had your exact problem, chased it for months. I took the whole car the the drive line shop. They inspected the mounting surface where the u-joint on the drive shaft connects to the rear end on the yoke. The two little nubbs that keep the u-joint centered were worn. This allowed the drive shaft to be out of center to the rear axle when bolted together. So I replaced the rear yoke and the problem was solved.

I'm going out now to crawl under and check the U joints,and the yokes. Also, the vibration decreases as the car slows down,and of course gets louder as the car speeds up.

Harmonic balancer damaged ??

Harmonic balancer damaged ??

BINGO!! it's cracked /engine is out of balance, if all other avenues have been checked. RPM increase. CHECK MOTOR MOUNTS/ cracked flywheel/ pressure plate gone to crap. :sad:

did you check to make sure the wheels are all mounted perfectly centered yet? if you have aftermarket wheels that don't center on the hub, it's easy for one wheel to get offset a little bit and cause a weird vibration.

Harmonic balancer is new. Pulled the driveline, U joints look good, no loose needle bearings, and plenty of grease. Pulled the tranny yoke, noticed scaring on the yoke in 2 places. Pulling tranny to go further.

So far, the front part of the teeth of reverse gears are chewed up, tail shaft bushing has a little wear but not extreme.

ok i'm gonna throw my 2 cents in. have you worked on your water pump and fan? i chased a vibration once and it turned out to be the bushing in the fan clutch was missing. i'm talking about the brass bushing that fits over the pump shaft and into the fan clutch housing that keeps it centered. i found my problem when the face of the water pump broke from the vibration. just a thought. good luck.

Hello, Looks like you are getting pleanty of help on this one. I had a similar problem years ago... Mine was a combination of driveshaft balance and bronze pilot bushing. And most recently a friend of mine with a similar problem found some wear in his fan clutch, just a slight wobble. Replaced the fan clutch problem went away. This was just last week.
Later.

I was going to suggest you drive the car until it starts to vibrate and put it in neutral and coast down the road and see if the vibration goes away as the engine would have gone back down to idle. But it sounds like you already have the transmission out.

maybe brake drums are not balanced? pinon angle?

If you did any engine work and replaced the water pump, A/C compresser, damper,alt, etc. check to see if the belts are in alignment. If any of the belts are not perpendicular to the pulleys, you will get a vibration which is RPM sensitive. Someone above suggested to determine if the vibration is speed sensitive or RPM sensitive. Speed sensitive usually points to wheels or suspension. RPM sensitive can be traced to the engine, its components or the transmission and or clutch/pressure plate or pilot bearing. I put in a new A/C system in my vette and had a vibration at 2800 RPM. It shook the shifter and my teeth. The A/C compresser bracket had to be shimmed to get the belt in alignment with the water pump pulley. Good luck and keep us posted. Jerry

Ok, the vibration seems to be speed sensitive as I recall, and when i get to the speed that it vibrates, I put the car in neutral and it seems to still vibrate but not as bad. Right now the driveline and front yoke are in the shop to have a new front yoke put on, new U joints, and have it balanced. The front yoke shows bad scaring in the areas where the bushing rides. Today, I'm going to check the pinion angle. Isn't there a plus and minus range for the angle? I will go look at the alignment of the belts to., I believe there is 1 belt that is not perfectly aligned with a pulley also.

I would like to know if you used the flywheel from the motor you took out. I believe you said it was vibrating before you changed the motor. If that is the case you may have the wrong flywheel or the flywheel may just be out of balance. Also if the drive shaft is to long it will bump the end of the tail shaft under torque because the pinion angle changes.I had a car that had a rhythmic pulse at higher rpm and that was the problem. This would also cause the scoring on the yoke. I hope its already fixed when you get this message

Yes, I did use the flywheel from the old motor, and that will probably be my next adventure, to have it balanced. I measured the driveline and gave the spec's to the driveline shop. So, they agreed with the length,and I 'll call them to ask about the yoke depth to make sure it is not to long. Right now I'm diving into the muncie 4 speed and found the mainshaft rear bearing is loose/tight when spinning the mid plate. Don't know if that is normal, so I'm going to change the mid plate for a steel, because I found a crack at the reverse idler area also. Don't know if the reverse idler would have anything to do with a vibration at high rpm/speed?

Any updates?

My vibration went away when I changed the water pump out. Bad bearing.

There is no updates yet. I am putting new trailer arms bushings in this week, changing out the air shocks back to factory,and ordering a rebuild kit for the muncie. The water pump is brand new. I can't wait to let you guys know if this fixes the mysterious vibration.

There is no updates yet. I am putting new trailer arms bushings in this week, changing out the air shocks back to factory,and ordering a rebuild kit for the muncie. The water pump is brand new. I can't wait to let you guys know if this fixes the mysterious vibration.

You better make sure you test drive after EACH repair/replacement of parts, otherwise you will never know exactly what the problem was.

Well so far the rear pinion wont adjust any higher than level (90degrees). I 'm trying to stay stock. If I have to go to adjustable upper control arms then I will. Would anything in the front end cause a vibration that is only felt through the shifter handle and vibrate the rear view mirror only to where you can't make out anything at speeds over 60mph?. The steering wheel never vibrates. It's is smooth

I have the exact same vibration. I have change numerous things as well. Right now Ihave the tailshaft out changing the bushing. Any luck finding this ?

Yes, I've had the driveshaft balanced several times with no change in the vibration i have to ask is the drive shaft installed correctly? if you look at the pictures in the assy manuel & see how the long & short area of the drive shaft is facing in the pictures versus what you have right now. i found out the hard way also when some one pointed out mine was backwards & vibrating at the same rpms yours is:yes:, hope this helps. bill:thumbsup:

My 68 Z/28 302 M-22 had a bad vibe at 4 grand in each gear. With through everything from water pump to the rear end including balancer, clutch, pressure plate, drive shaft, 4 speed rebiuld & water pump. I determined that it must be a bent input shaft on the tranny. Yanked it out, tore it down and brought the input shaft to the machine shop....perfect, no run out!! If I wasn't bald I'd pull my hair out!! Oh well, I 've got the trans out, might as well rebiuld it again. Pressed the shaft off the center main bearing and there it was. A small nick in one bearing ball. Replaced it and it runs like a watch now to 7 grand. I was so relieved. The trans shop that rebuilt the 4 speed didn't change that main bearing. I got a "how to rebiuld your trans" vidio and did it myself.

Just a thought. I had two cases where the differential pinion bearing went bad. It vibrated so bad that it would hurt your hand to hold the shifter stick.

Yeah Rog, that video worked pretty good. It is the only VCR tape that I have watched more than once! VCR? WTF is that? haha

Is the vibration still there with the tranni clutch and presure plate off the car ??