icanfixitforyou

I have a high speed drivetrain vibration that is most noticeable under hard acceleration. My motor has less than 200 miles on it. I have a Richmond 5 speed transmission in a 1979 L-82. I have installed new pilot bearing in the motor and installed a new tail housing and bushing on the trans. The driveshaft has been balanced. The problem was more noticeable before all of this work was done, the stick used to chatter and vibrate pretty good and make a bunch of noise. Now it is quiet, but not as smooth as I was hoping for.

Does the higher compression from my new 383 stroker contribute to this?

Is my old Richmond 5 speed loose internally somewhere?

Or am I just expecting too much from a 27 year old muscle car?

icanfixitforyou

OK - I realize that the weather is nice and those of us who can are out driving our C-3's, but doesn't anyone have any feedback for me?

revitup

I have a high speed vibration also at about 70+ that's much more noticable now that I've replaced all my suspension bushings (with poly). I have a good amount of play at the yoke/tailshaft bushing so I'm replacing the bushing next weekend hoping that's the issue. If that's not it, I'll try something else. I don't think you're expecting too much. I'm expecting a smooth highway ride. Thought about something as simple as rebalancing tires?

icanfixitforyou

I have pretty much narrowed it down to the drivetrain, no problems when coasting, just when under load.

luerja

I get the same thing between 3500 and 4000 RPM under hard acceleration. I haven't solved mine yet.

Interesting to see what you come up with.

...Roger...

So you say when you push the clutch in and coast the vibration goes away?Your drivetrain is still going the same speed.Is there a differance if you just kick it in neutral verses pushing the clutch in?

rihwoods

Just went thru this on my 78...very visible in the shifter...I replaced all the spring washers and spring clips on my M20 linkage...now very smooth..but...when backing off from 75-80, I get a resonance from the exhaust...
Can you give a more detailed description ? Vibration in these Vettes can be simple or complex...so a better description will help...also,how old is your Richmond?
Rich

79 Bullet

I have a similar issue and I haven't gotten around to fixing it but a few things that I am considering that I have read on past posts are
1) type of clutch - some have complained of the dual friction clutches with the weights in the diaphrams as a possible cause.
2) play in the yoke in the rearend
3) transmision mount bushing is worn on my car ( 4 -speed)

Bob Onit

I had that problem... took me a while to figure out that the engine was simply running rough above 2,500 RPM

Tune up, rebuilt Distributor, carb........ Im vibration free @ 100 + MPH

revitup

I'll report whether the tailshaft bushing replacement cures mine or not. I know that won't help icanfixitforyou since he's already been that route.

Richieboy

Clutch only- clutch to wheels linked; engine not connected to trans

Neutral w/o clutch- engine and trans input shaft connected;
rear end and trans output shaft linked

Neutral w/ cutch- engine alone, input shaft alone, output linked to rear wheels

...Roger...

Lee -try these combinations and record what happens. If your at 80 and in high gear and push the clutch in then everything in the drivetrain including the clutch disc is still running 80.If your vibration goes away its going to be engine related.Flywheel,clutch,water pump,fan clutch,harmonic balancer -bad balance on crank and so on.Let us know !!!

revitup

Well, I replaced the tailshaft bushing in my quest to eliminate my high speed vibration problem. No difference. Guess my next move will be to replace both U-joints and have the driveshaft balanced unless someone has another suggestion. The front U-joint felt somewhat stiff when I tried to move it while the driveshaft was disconnected for the tailshaft bushing replacement.

croaker

I've got the same problem good luck

s car go

I went thru the same crap that everyone mentioned here. I changed the length of the driveshaft twice. Through it all I had a high speed vibration that finally went away when I changed the U-Joints to a high quality brand. The drive shaft was balanced 4 times and never showed a problem on the bench. Only in the car. I never would have suspected them if I had not seen it for myself.

...Roger...

s car go -did you do this change of u-joints personally?

revitup

What brand U-joints did you use?

s car go

I did not change them myself. It was done during the last time it was balanced at Northwest Driveshaft in Houston. I dont remember the brand - he said it was a high quality brand - they dont use junk - probably a spicer. I know the one at the transmission end is a spicer because it is a 1330-1350 crossover type. But that one was not the problem. I never would have believed that the joints could be the culprit. I was talking to the shop that makes the driveshafts for "Classic Chevy 5 Speed" product. When I discussed what kind of problem I was having he immediately knew the joint was the problem. He said he sees it all the time. I was not sure I believed him but I had no other suggestions to try. So I changed them and the problem was gone. I suspected all sorts of other things related to the tranny, differential, half shafts, position of the moon, state of the economy etc.

He was right - never would have guessed it.

...Roger...

Did he say what was wrong with the other joints that would cause a vibration?

TopGunn

Interesting solution, I've been trying to solve the same exact thing with mine and have replaced the U-joints on the drive shaft with Spicers a while ago. Balancing mine made a huge difference but it's still there at 70 mph when applying throttle or at light cruise. I've rebuilt the rear bearings, half shaft joints, new tranny tail shaft AND different motor/flywheel/clutch/pilot, and it's still there.

Maybe I should try a differnt U-Joint on the drive shaft. (or change the damn headlight bulbs )