Stroked96Bowtie

iTrader: (22)

Over 70mph in gear OR in nuetral over 70mph...same vibration. Only things that Ive ran into, similar issue to yours was with a driveshaft out of balance or wheels out of balance. Sometimes it doesnt take much to throw a driveshaft off, if it was dropped, etc...could do it. When you did the clutch change, did you use ANYthing from the old setup? Or was it ALL new? Then again, if it was on the clutch side you should be able to feel that giving it throttle in your driveway.

Looks like you've tried 2 diff driveshafts...same exact vibrations? Are the wheels new? Try to think about what you may have changed just before it started.

96capricemgr

iTrader: (1)

Not likely the problem but in all my reading the pilot bearings are MUCH more troublesome than bushings, so if you find yourself taking this back apart I would swap that back to a bushing.

ThoR294

iTrader: (6)

It happens in gear slightly, but virtually goes away when you hit the gas. If you push the clutch in, its real bad. Real bad in neutral, same intensity as pushing the clutch in.

LightningTeg

So if your rolling at 70 and put the clutch in it starts doing it badly? I would suspect a bad joint or drive shaft. When its under load, whatever slack in the system gets binded back up and you get less vibration it sounds like

ThoR294

iTrader: (6)

Yes. You can kinda feel it while its in gear decelerating, but if you push the clutch in it feels like hell. If you accelerate it virtually goes away. I know, it sounds like and feels like a driveshaft. I've balanced and had 2 new u joints on the steel DS (which is in it right now), and an aluminum driveshaft out of an LS1 with new joints did the same thing. I'm going to measure it and throw a sweet PST driveshaft into it and see where that leads me.

LightningTeg

Get it up on a lift running and see if you can find the culprit

93M6Formula

Would bad motor mounts somehow cause a vibration?

ThoR294

iTrader: (6)

vibration when you hit the gas on take off, or rev it freely.

Motor mounts keep the motor in place. So if the motor gets torqued, itll move around pretty good if the mounts are bad.

93M6Formula

Just throwing out ideas since about everything else has been covered.

ThoR294

iTrader: (6)

haha yeah my next idea is LS1 car

speedtigger

iTrader: (16)

You might have your transmission tail shaft bushing checked. When they are heavily worn, you can get a vibration that is more intense when the drive train is not loaded such as when coasting.

93 LT1 Vette

A constant timed vibration is generally caused by a rotating mass.

Driveshaft
wheels
wheel bearings
brake discs
tires
Ring and pinion
axle shafts
Clutch/throwout bearing
flywheel
pressure plate
transmission main shaft
crankshaft
pilot bushing in the back of the crank
harmonic balancer
crank pullies
power steering pump
alternator
A/C compressor

Now what on this list changes in neutral or when you push in the clutch or what do you unload that could cause a vibration that you have not changed or looked at.

Engine RPM's drops
clutch disc
throw out bearing
Drivetrain load lessens.

nascarnate326

iTrader: (1)

axel bearings?

F0x Slaughter

I have my pinion angle set at 0. S60 was just installed and Strange driveshaft. Got on the freeway today for the first time and 80+ she was vibrating. Going to adjust the pinion angle and she how she likes that.

ThoR294

iTrader: (6)

I have heard about this. Would both transmissions really have the same issue?

the bottom half of the list is out of the question because its a vibration on the output shaft side of the transmission. I shut the motor off in neutral and its still there. this means the motor is not moving at all

unioncarpenter84

iTrader: (22)

ive got the same problem just wana drive it off a cliff lol

i got new

umi lca
umi adj panhard bar
new qa1 shocks
new wheels and tires balanced
steel driveshaft balanced and new spicer u joints
new trans mount
tired poly mount



and it still does it makes not a bit of sence the cars did not come like this from the factory so its gotta be fixable!

unioncarpenter84

iTrader: (22)

okay guys i think i may of found the issue im going to do this within the next few days

watch the last few minutes of this video on the link its bout the u bolts being to tight causing 80 percent of vibration!!!

wonder if this is true

i kno i crank mine down so it doesnt come loose

but heres the link

http://www.hotrodhotline.com/md/html...asurements.php

chino_man279

iTrader: (7)

Thor the more you describe your problem the more it sounds EXACTLY like the issues I was having. I got to the point I thought the car was going to explode so I quit driving it.

ThoR294

iTrader: (6)

I can jack my car up and put 2x4s under the rear wheels so I can get under the car and to measure the driveshaft (for PST)? or does it have to be completely level... (i.e. alignment rack)?

chino_man279

iTrader: (7)

I did mine in the driveway. I put a couple 2x4's under each tire so I could crawl underneath. Measured with a standard tape measure and called. If I remember correctly I got mine from Bob who is now at Brute Speed. Been a long time since I got mine... I just made sure the suspension was loaded the same as it would be going down the road.