Bad Vibration
Thread Starter
12 Second Club
Joined: Aug 2003
Posts: 270
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From: Chicago IL
Bad Vibration I have a very bad vibration in my drivetrain at any speeds above 15mph. I searched for other vibration threads and most where at certian speeds (usually high).
Recent Mods:
Strange 12 bolt
1350 yoke in Stock DS (pressed in with vice by me)
Spohn Adj. Torque Arm
Spohn Adj. LCAs and relocation brakets
Spohn Adj. Panhard rod
I know any of those things could probably cause the vibration, I have ordered a new DS from Billingsley which I hope may resolve the problem. Does anyone have any other suggestions, could it be my pinion angle? I set it to -1 using spohn's instructions which did not indicate the rear had to be a ride height (it wasn't).
Recent Mods:
Strange 12 bolt
1350 yoke in Stock DS (pressed in with vice by me)
Spohn Adj. Torque Arm
Spohn Adj. LCAs and relocation brakets
Spohn Adj. Panhard rod
I know any of those things could probably cause the vibration, I have ordered a new DS from Billingsley which I hope may resolve the problem. Does anyone have any other suggestions, could it be my pinion angle? I set it to -1 using spohn's instructions which did not indicate the rear had to be a ride height (it wasn't).
TECH Veteran
Joined: Aug 2003
Posts: 4,954
Likes: 1
From: Kent WA
Just make sure everything is lined up nice and straight... my Moser was off just a bit and has been the cause of a major driveline vibration. It was barely noticeable with the stock driveshaft, mostly because I think it had a little give to it. I switched to Denny's Nitrous Ready, and the vibration increased a ton... mostly because it doesn't have any give in it at all, so it is less forgiving of stuff being out of alignment.
Had to put the car up on a rack, and straighten everything out... a big PITA. They say these aftermarket rears are direct bolt-ins, yeah right.
Had to put the car up on a rack, and straighten everything out... a big PITA. They say these aftermarket rears are direct bolt-ins, yeah right.
Josh, have you tried it up on jackstands with the wheels off ? I know you didn't change the wheels, but it would reduce the load on the axles.
Also, you might remove diff and run it, that would allow only the ds and pinion to spin, taking the axle and diff out of the equation.
Also, you might remove diff and run it, that would allow only the ds and pinion to spin, taking the axle and diff out of the equation.
Thread Starter
12 Second Club
Joined: Aug 2003
Posts: 270
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From: Chicago IL
Originally Posted by TRex
Josh, have you tried it up on jackstands with the wheels off ? I know you didn't change the wheels, but it would reduce the load on the axles.
Also, you might remove diff and run it, that would allow only the ds and pinion to spin, taking the axle and diff out of the equation.
Also, you might remove diff and run it, that would allow only the ds and pinion to spin, taking the axle and diff out of the equation.
I recently installed a Moser 9", I have been trying find a vibration in the rear of my car also. I was wondering since my car is lowered and I know the rear is shifted 1/4" to the left if this may be the problem? I plan on getting an adj panhard bar anyway but just did'nt know if maybe this was contributing to the vibration.
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Originally Posted by Tranzor_Z28
if it is off, it can contribute to the vibration because that means your drivetrain isn't lined up properly... the adj. panhard should help fix that.
11 Second Club
Joined: Dec 2002
Posts: 1,498
Likes: 10
From: long island, ny
i have almost the same setup but with a moser 12 bolt and i have the panhard bar
i have everything as straight as i can get it; wheels are centered under the car notic that wh but ien toy senter the wheels the pinion yoke is still closer to the the passanger side which is odd
only vibration i have is on decel and its not that bad but the rear wines in decel
i have everything as straight as i can get it; wheels are centered under the car notic that wh but ien toy senter the wheels the pinion yoke is still closer to the the passanger side which is odd
only vibration i have is on decel and its not that bad but the rear wines in decel
If it is a bad vibration & it gets worse undr accel it is likely the pinion angle.
You have the angle gauge right? Look at this:
http://www.rosslertrans.com/Tips/Pinion.htm
It has to be checked with the car level & rear axle at ride height.
Dont drive it with the angle off real far can cause problems.
You have the angle gauge right? Look at this:
http://www.rosslertrans.com/Tips/Pinion.htm
It has to be checked with the car level & rear axle at ride height.
Dont drive it with the angle off real far can cause problems.
Thread Starter
12 Second Club
Joined: Aug 2003
Posts: 270
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From: Chicago IL
Originally Posted by wrencher
If it is a bad vibration & it gets worse undr accel it is likely the pinion angle.
You have the angle gauge right? Look at this:
http://www.rosslertrans.com/Tips/Pinion.htm
It has to be checked with the car level & rear axle at ride height.
Dont drive it with the angle off real far can cause problems.
You have the angle gauge right? Look at this:
http://www.rosslertrans.com/Tips/Pinion.htm
It has to be checked with the car level & rear axle at ride height.
Dont drive it with the angle off real far can cause problems.
i have checked the pinion angle many times and set it at -2 and 0 it still vibrates. i am beginning to think its the torque arms. there are many of these issues with spohn torque arms out there. check on ls1 and ls2 and there are more. i have talked to spohn before and they said they have never heard of it. i brougt my car to a local drivetrain shop and he said that the shackle setup moves thus causing the angle to change. spohn said that the pinion angle doesnt change WTF. these torque arms are the craziest things. noone can figure them out. it seems like maybe there is a bad batch or jig and we have untrue ones or something. what can explain this. i cant go over 80 without feeling like my car will explode and under decel i get clunk clunk clunk and worse if i go over a defect in the road. it sounds like my drivetrain will fall off my car. i have double and triple checked all the bolts. my t/a bolts have never gotten loose. talk about driving you insane 
. i am at my wits end with this t/a. that shackle setup has to move. i wish i can get it on camera.
. i am at my wits end with this t/a. that shackle setup has to move. i wish i can get it on camera. Thread Starter
12 Second Club
Joined: Aug 2003
Posts: 270
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From: Chicago IL
Originally Posted by wrencher
Still sound like P/A could be the problem, re-check the angle.
If you have to run it at ride height in the air on jack stands & see if that helps chase it down.
If you have to run it at ride height in the air on jack stands & see if that helps chase it down.
Better make sure I back into the garage just in case.
Originally Posted by bmfcamaro
i have checked the pinion angle many times and set it at -2 and 0 it still vibrates. i am beginning to think its the torque arms. there are many of these issues with spohn torque arms out there. check on ls1 and ls2 and there are more. i have talked to spohn before and they said they have never heard of it. i brougt my car to a local drivetrain shop and he said that the shackle setup moves thus causing the angle to change. spohn said that the pinion angle doesnt change WTF. these torque arms are the craziest things. noone can figure them out. it seems like maybe there is a bad batch or jig and we have untrue ones or something. what can explain this. i cant go over 80 without feeling like my car will explode and under decel i get clunk clunk clunk and worse if i go over a defect in the road. it sounds like my drivetrain will fall off my car. i have double and triple checked all the bolts. my t/a bolts have never gotten loose. talk about driving you insane . i am at my wits end with this t/a. that shackle setup has to move. i wish i can get it on camera.
. i am at my wits end with this t/a. that shackle setup has to move. i wish i can get it on camera.
Thread Starter
12 Second Club
Joined: Aug 2003
Posts: 270
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From: Chicago IL
Originally Posted by 991LE
I would vote for pinion angle.
Did you ding up the driveshaft when you installed the Ujoints?
Did you ding up the driveshaft when you installed the Ujoints?
The vice did dig into the DS pretty hard when I was installing the ujoint. Hopefully the Strange DS will be waiting at home.
Originally Posted by SapphireHawk
I'm thinking it is either the pinion angle or the rear not being centered with the adjustable panhard rod.
The vice did dig into the DS pretty hard when I was installing the ujoint. Hopefully the Strange DS will be waiting at home.
The vice did dig into the DS pretty hard when I was installing the ujoint. Hopefully the Strange DS will be waiting at home.
Originally Posted by SapphireHawk
Have you tried swaping in the stock T/A to see if it fixes the problem?
i broke my stock t/a after getting the moser rear, but there was vibration with the stock one for the short time it lasted. i also have an adj panhard i thought that that might fix it and it didnt help.
Originally Posted by bmfcamaro
i broke my stock t/a after getting the moser rear, but there was vibration with the stock one for the short time it lasted. i also have an adj panhard i thought that that might fix it and it didnt help.