jyeager

Which inigma? Everyone who experiences this could have a different cause. Just to summarize my thinking on the possible causes:

1) anything that rotates can be out of balance. Some are unlikely culprits (like accessory pulleys, engine rotating assembly) but the likely ones are:
a) flywheel, clutch, PP (MT only)
b) flexplate (auto only)
c) driveshaft
d) axles
e) wheels/tires

2) something bent/damaged
a) axles
b) rims
c) driveshaft
d) u joints
e) damaged tranny mount

3) something worn
a) pilot bearing
b) slip yoke bushing (in tranny tailhousing)
c) tires cupped (most likely culprit in general!!!)
d) u joints
e) axle bearings
f) pinion bearing
g) ball joints, tie rod ends, idler arm
h) rubber suspension bushings

4) something out of adjustment
a) pinion angle (due to lowering, or changing tranny mount, or changing torque arm
b) loose suspension parts.

M29_Formula

My vibration problem started after I installed my Spohn Adj. body mounted T/A. It starts at about 70mph and gets really bad around 80-90mph and seems to get a little better as you go up past 100mph but is still there.

My driveshaft has been balanced and checked over by Northern Colorado Driveline -- one of the best driveline shops in the area so I know that it is not the problem.

Next weekend I'm going to put my car up in the air on the alignment rack at work and check my pinion angle. I'm also going to try the rotate the driveshaft trick to maybe bring it into phase. I'll let you guys know what happens.

BADSZ28

iTrader: (39)

I have a vibration at 50+ and I have a new 9" with all new bearings, shafts and seals, new DS and wheel were just fine prior to all this being installed. Very frustrating. Any ideas? Oh and car is stock hieght.

blueovalbeater

iTrader: (1)

dont know if this has already been mentioned yet but on my old 94' Z28 i had installed a polyeurothane tranny mount.....well it comes with a 1/8 inch metal plate that the instructions say you need to install. well a while after I got a vibe 75ish so I went through bearings,u joints,balanced the driveshaft ect. well soon I found out that our cars trannies dont like the angle that the extra plate puts it at. i removed the plate and the vibes went away. hope i could help some of you vibe guys out. later

Cal

iTrader: (1)

This is a very long thread; didn't have time to read the whole thing, but thought I would mention this:

Having deep rear end ratio gears can cause high speed vibes. I get vibrations that peak at about 145 mph with 4.11 gears. This is because the drive shaft spins faster with deep gears, and there is a point that it will resonate and shake, even if perfectly balanced. The solution is a carbon fiber drive shaft and/or higher ratio rear end gears. I'm swapping out my 4.11's for 3.50's.

BlackHawk131

iTrader: (31)

One thing everyone has to remember is that all LS1 drive shafts are 0 balanced and it does not matter how it goes in the car.

kenkaru

Yah, I see this mentioned a lot and I even tried it but I haven't seen rotating the d/s fix a single persons problem so it's probably just one of those things that worked in the 70's or something.

BADSZ28

iTrader: (39)

Well I found my vibration. Turns out the rear sits soo far back that the DS does not slip in enough and is loose on the output shaft. So I am oging to have my LCAs put into stock location holes till I can get my LCA brackets adjusted properly. I will keep everyone posted.

jimbo98z

iTrader: (3)

Just put in a Moser 12-Bolt with 3.90's and I am having the same shimmy issue starting around 70. Shimmy goes away when you put the clutch pedal in, so I'm thinking mine is either tranny, clutch, or flywheel. Gears make a hell of a lot of noise too when maintaining any speed about about 40.
Car's back home to get checked out by a guy that builds rear ends and transmissions for race cars as a specialty. Figured it would be best to have someone who really is a professional check it out. Will repost when I hear back.

ninobrn99

iTrader: (8)

Just FYI, mine is almost completely gone. its about as good as its gonna get with the chassis mounted TA and a 9". It turned out my pinion angle was set at +10 degrees my wife said the car is so much better now!

Speedn108

This is probably your problem (flexplate) I know its mine



And other than the annoying vibration this is what it caused, two times. cracked the tailshaft.

Dragula

iTrader: (5)

Here's what I did to solve this issue.

https://ls1tech.com/forums/suspension-brakes/508662-ta-axle-vibration-solved-almost.html

BlackHawk T/A

iTrader: (3)

Same here, and it doesn't seem to matter whether its an A4 or an M6 car. Mine stops vibrating in Neutral but when you go back into D it starts again (around 65mph). The Prothane tranny mount multiplied the issue so i'm gonna try a rubber mount again, then look into the problem further after I have a good TA setup to the right angle.

fenix99

iTrader: (1)

my car started doin this little shaking crap when i put in the Poly Energy Suspension Trans mount...im about to go back to stock or the 1LE mount, which is still rubber i believe...as soon as i put in the trans mount and drove the car i noticed the vibration

im guessing just checking all the axle bearings and checking or even replacing the motor mounts/trans mount wouldnt hurt..especially if you havent done so in a long *** time. just my .02

BlackHawk T/A

iTrader: (3)

You can rule out most things pretty quickly by going into N while driving and seeing if it stops.

Mike2000Z28

So after replacing everything out back, might have found the vibe. I'm going to pull my motor in a couple of days. It just started to make a valvetrain tick but it is alot louder and the car started running like crap. The noise is coming from the number 7 cylinder. Since my first day at the track over a year ago I have been playing around with a vibration in the car. IF the car is in N and you hit 1700 to 2000rpm there is a vibration. The vibration on my return trip to my motor guy has the vibes now down in the 60-65mph range where before last weekend it was up around 70-75mph.

HowellSoccer88

iTrader: (18)

Mine went away when I dumped the Spohn tunnel mounted torque arm and went with a tranny mounted set up...just my .02

SailorZ28

Ok my Z is pretty much stock except for some vette rims/tires and exhaust. I have a vibration also, in the steering wheel/front end, but at speeds of between 55-75. At lower speeds and at higher speeds I don't have any vibration at all. What might be causing this? It seems like most of you are experiencing problems at higher speeds, mine are at cruising speeds (NOT good for a daily driver!). It hops so bad that it causes weird wear patterns on my tires...and tires are NOT cheap!

Please help!

The car has 60k miles, M6, and it's never been to a track.

ninobrn99

iTrader: (8)

sounds like the tires arent balanced correctly or the alignment is off.

SailorZ28

That was my thinking too, but it has done it with the old stock rims/tires and the vette tires/rims I just put on. Same exact vibration. Would a bad alignment cause a vibration or just the car pulling in one direction or the other?