Suspension & Brakes - Bad Vibrations Above 60 mph




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Turnin20s
06-15-2008, 01:56 AM
Finally got my car all finished up today and got to take it out for a spin. Everything went great, but my new gears are making a little noise which isn't a problem since its going to get a 9" here soon. But anywhere above 60 mph I have a really bad vibration coming from the rear of the car. If I accelerating hard it won't do it until I let off or start decelerating, but its pretty bad. It didn't do it with the A4 but I know its not coming from the tranny. It might be my driveshaft, but why would it start now? I just changed the U-joints so I'm pretty sure thats not the problem and everything else is tight. The pinion angle is set at -3. I still have a steel driveshaft, and it almost feels like it is the driveshaft, but like I said it never did it before.

I'm going out in the morning to look it over but if you have experienced problems like this I'd appreciate the help.

Thanks in advance

BTW I'm running a Spohn tunnel mounted torque arm, UMI tubular LCAs, and a UMI nonadjustable panhard bar. The rest of the suspension is stock for the most part.


shoemike
06-15-2008, 02:46 AM
Finally got my car all finished up today and got to take it out for a spin. Everything went great, but my new gears are making a little noise which isn't a problem since its going to get a 9" here soon. But anywhere above 60 mph I have a really bad vibration coming from the rear of the car. If I accelerating hard it won't do it until I let off or start decelerating, but its pretty bad. It didn't do it with the A4 but I know its not coming from the tranny. It might be my driveshaft, but why would it start now? I just changed the U-joints so I'm pretty sure thats not the problem and everything else is tight. The pinion angle is set at -3. I still have a steel driveshaft, and it almost feels like it is the driveshaft, but like I said it never did it before.

I'm going out in the morning to look it over but if you have experienced problems like this I'd appreciate the help.

Thanks in advance

BTW I'm running a Spohn tunnel mounted torque arm, UMI tubular LCAs, and a UMI nonadjustable panhard bar. The rest of the suspension is stock for the most part.

that`s a lot of pinion angle for the streets.

Turnin20s
06-15-2008, 11:57 AM
I thought thats what its suppost to be set at according to BMR. You think that might be the problem? I guess I can take some out and see how it feels. Its kind of weird though, if I'm on it hard it won't vibrate until I let off to slow down but it vibrates hard. I'll take some angle out today and see if it helps

Thanks for the reply


shoemike
06-15-2008, 12:41 PM
if you didn`t have it before then it most likely is the reason.
i`d recommend no more than -1* for street driving.

Turnin20s
06-15-2008, 10:15 PM
Ok well today I went out and adjusted it and its still there no matter what I do. The only thing that I did to the driveshaft was add new u joints so mabye they are bad or I installed them wrong, probably not but it has to be something.

Now when the pinion is set should the pinion york point to the ground or the bottom of the car? I tried both ways to make sure that I didn't do something wrong and it made absolutely no difference. The car starts to vibrate bad at about 65 and up, nice and smooth before that

BobDoLe
06-15-2008, 11:11 PM
not sure how relevant this is, but it may be worth mentioning that my auto did the exact same thing with a poly mount.

99mTealB4C
06-16-2008, 01:01 AM
ive got the same problem right now i have went through 3 u joints my spohn trq arm is set at -3 if its supose to be set at like -1 then is it going to be hard on u joints at the track when i go? whats factory pinon angle on a auto car?

Turnin20s
06-16-2008, 01:25 AM
I highly doubt that a poly tranny mount will make the rear of the car feel like its going vibrate apart. Not being a dick, but I know the tranny mount is not the problem.

99 does your car vibrate extremely bad above 60 mph? Have you found a solution?

99mTealB4C
06-16-2008, 01:39 AM
well i know that i didnt have a vibration at all untill i ut the torqe arm on and set it to -3 like most place say but yeah mine vibtrate starting at 50mph i took it up too 100mph the first time the u joint blew up at 100 since ive put two more in and babied it still havent figured it out i though i had bad batch of u joints so tommorow im going to throw a diffrent brand u joint test it then if thats not it im going to re adjust torque arm

Xsta Z 28
06-16-2008, 08:08 AM
Are you sure you are reading the TA gauge from the correct side??? . . . I question if you have the agle BACKWARDS . . .

Cliff notes:

Old stock TA, no vibration . . .
New adjustable TA, vibration . . .
After new TA, the universal blows apart????!!!!
Something is installed wrong!

99mTealB4C
06-16-2008, 08:35 AM
i didnt have any install instuctions so im not 100% sure its installed correctly but every thing looks to be right. if someone has a copy of the instruction pdf file or something please let me know.

BMR Tech
06-16-2008, 09:01 AM
Finally got my car all finished up today and got to take it out for a spin. Everything went great, but my new gears are making a little noise which isn't a problem since its going to get a 9" here soon. But anywhere above 60 mph I have a really bad vibration coming from the rear of the car. If I accelerating hard it won't do it until I let off or start decelerating, but its pretty bad. It didn't do it with the A4 but I know its not coming from the tranny. It might be my driveshaft, but why would it start now? I just changed the U-joints so I'm pretty sure thats not the problem and everything else is tight. The pinion angle is set at -3. I still have a steel driveshaft, and it almost feels like it is the driveshaft, but like I said it never did it before.

I'm going out in the morning to look it over but if you have experienced problems like this I'd appreciate the help.

Thanks in advance

BTW I'm running a Spohn tunnel mounted torque arm, UMI tubular LCAs, and a UMI nonadjustable panhard bar. The rest of the suspension is stock for the most part.

You said the rear gears are making a noise? if there is a gearset issue the manual transmission is going to make it more pronounced....

Turnin20s
06-16-2008, 12:52 PM
You said the rear gears are making a noise? if there is a gearset issue the manual transmission is going to make it more pronounced....

Yeah the gears make a little noise on the inbetween when I'm not on the gas and not quite on a decell. Its not terrible, I can handle a little gear whine, but the vibration has to go. On saturday I'm going to get and LS1 driveshaft. I had the TA installed in my car with the auto and it didn't make the vibration, but I have made so many changes the past few months its hard to guess where to start.

But is the pinion suppost to point to the ground or to the bottom of the car? I have tried both ways thinking I was wrong and the vibration is still there. I had it set at -1 and -3 and +1 and +3 and the vibration is still there.

The changes since the car was auto are....4.10 gears, new u joints, and I did the heater hose mod on the rear springs, but other than that everything was done on the front. There was the M6 swap, spec stage 3 clutch, new rings, new sway bar, and the new tune and I think thats it.

I'm just going to take it easy on the car and get some miles on everything this week and wait till the weekend and get new u joints on the LS1 shaft and see if it fixes my problem, if not I'll pull the rear cover off and see if I can fix my gear whine and find out if that makes anything better.

I appreciate all of the help guys, but this vibration has to go. I don't have my stock TA, but mabye I'll have a new BMR today if I win the contest :D Otherwise I'd throw it back in and see if the vibration goes away

Turnin20s
06-16-2008, 12:58 PM
Ok never mind, I watched the video again and the pinion is suppost to point towards the ground. Thats how I have it so right now I have my pinion set at a -2 and the vibration is still there. Everythings tight and my tires are balanced right

CranMaro99
06-16-2008, 03:08 PM
Mine started doing the same thing after my poly mount. Anything above 65. Stock suspension right now too.

Obviously the vibration might have already been there, but I didn't FEEL it until I did the poly mount.

Viper
06-16-2008, 08:20 PM
I've got a poly mount and a RandomTech adjustable torque arm set to -2, nevr had a problem. And I'm lowered. I'm leaning towards gearset like BMR said. If you suspect driveshaft have yours balanced or get the new one you are getting balanced. Another idea is to flip the driveshaft 180 degrees.

Turnin20s
06-17-2008, 02:33 AM
^^ Yeah I was told that, but I really want the aluminum shaft and the price is right. I'm going to take a look at the gears when I pull the shaft and if that doesn't do it I'll swap out the tranny mount, but its not coming from the tranny its coming fron the rear. I also had the poly mount with the A4 and it didn't do it.

DopdBrd
06-17-2008, 09:35 AM
Hey man, I am having the same problem....I went through two rear ends and finally installed the S60. I adjusted the TA to -2 degrees and used BMR's method of adjusting it.

When I drive the car under slight acceleration I get a very slight vibration in my whole drivetrain. Then, when on the highway, I decell and get a BAD vibration coming through the whole drivetrain.

I really don't know what it is and can't think of what to do. I changed the fluid in the Dana at 1000 miles like suggested and didn't notice anything wrong in the rear and the gears looked like they were fine.

If anything I might go back to 0 or -1 degrees since it gets driven mostly on the street and see if that will help.

Anyone else?

Viper
06-17-2008, 09:42 AM
Both you guys (DopdBrd and Turnin20s) try flipping the driveshaft 180 degrees to see if it helps. What this means is unbolt it from the rear, turn it 180 degrees in your hand and rebolt it back up. Takes 10 minutes; try it today.

DopdBrd
06-17-2008, 09:49 AM
JUST FYI, I have been told that maybe there is something broken or loose in my tranny. When I blew up my first rear the tranny started acting up and after the second rear went the tranny was really weird.

I called strange when I was driving my car cross state because of the vibration and they said that there could very well be something wrong with the tranny causing the vibration.

DopdBrd
06-17-2008, 09:50 AM
Both you guys (DopdBrd and Turnin20s) try flipping the driveshaft 180 degrees to see if it helps. What this means is unbolt it from the rear, turn it 180 degrees in your hand and rebolt it back up. Takes 10 minutes; try it today.

Thanks man, I'll try that tonight when I stick my Adj LCA's on.

Turnin20s
06-17-2008, 11:42 AM
The only thing I have against something being broken in the tranny, is that I can push in the clutch or put it in neutral and the vibration is still there. I have anyother rear laying outside at my parents house, but I don't want to swap again. Mabye I'll just drop the cash and get my gears set right by a pro.

And it will take more than 10 minutes to flip the drive shaft. Not trying to be a dick, but you have to press the yoke off and repress it back on in the back. It takes me about 20 minutes just to get the damn shaft out :)

I'm still going to get the LS1 shaft on saturday and install that and see if it gets better if not I'll pull my cover off and see how everything looks. But like I said its just a slight whine coming from the rear, nothing terrible.

Mabye I'll grab a tranny mount from autozone and see if it makes anything better, but it really doesn't seem like it would be a tranny mount.

Thanks again guys

DopdBrd
06-17-2008, 12:36 PM
The only thing I have against something being broken in the tranny, is that I can push in the clutch or put it in neutral and the vibration is still there. I have anyother rear laying outside at my parents house, but I don't want to swap again. Mabye I'll just drop the cash and get my gears set right by a pro.

And it will take more than 10 minutes to flip the drive shaft. Not trying to be a dick, but you have to press the yoke off and repress it back on in the back. It takes me about 20 minutes just to get the damn shaft out :)
I'm still going to get the LS1 shaft on saturday and install that and see if it gets better if not I'll pull my cover off and see how everything looks. But like I said its just a slight whine coming from the rear, nothing terrible.

Mabye I'll grab a tranny mount from autozone and see if it makes anything better, but it really doesn't seem like it would be a tranny mount.

Thanks again guys

I don't think u quite understand what he is saying, he doesnt want you to flip the driveshaft, but rather ROTATE the driveshaft in the car.

So all you have to do is take it out of the rear, turn the driveshaft 1/2 a turn, and then put it back in the rear end.

RIGHT?

BMR Tech
06-17-2008, 01:32 PM
I don't think u quite understand what he is saying, he doesnt want you to flip the driveshaft, but rather ROTATE the driveshaft in the car.

So all you have to do is take it out of the rear, turn the driveshaft 1/2 a turn, and then put it back in the rear end.

RIGHT?


Right...

Turnin20s
06-18-2008, 02:52 AM
Oh I see, I thought he meant to flip the whole shaft 180*

Viper
06-18-2008, 04:46 PM
No; dopbrd did you try it yet?

Ryans99ls1
06-18-2008, 05:23 PM
When you put in a poly mount, it raises the back of the trans about an 1/8th of an inch, which does change the driveline angle.. So if i were you, id set the angle on the TA to compensate for that.

I didnt read every post, so im not sure if you already tried anything like that.

DopdBrd
06-18-2008, 06:26 PM
No; dopbrd did you try it yet?

Not yet, planned on working on the car and everytime I do something else comes up.

ls1n00b
06-18-2008, 09:01 PM
motor mounts maybe?

Grn4fbody
06-18-2008, 10:19 PM
-3 is a lot for a street car, set it to -1 or -1.5 and you should be set, also how are you getting your pinion angle?

Turnin20s
06-19-2008, 02:56 AM
Pinion angle has been set per BMRs clip and the traditional way by just putting it on the TA bracket that bolts to the rear.

Motor mounts are new also, but were used with the A4 and nothing was strange then. I have a few things to check out but I'm on 10 hour days and getting burned out LOL but the extra money is nice

CranMaro99
06-19-2008, 03:04 AM
No; dopbrd did you try it yet?

Get back to us, dopbrd, when you do this.

CranMaro99
06-19-2008, 03:04 AM
When you put in a poly mount, it raises the back of the trans about an 1/8th of an inch, which does change the driveline angle.. So if i were you, id set the angle on the TA to compensate for that.

I didnt read every post, so im not sure if you already tried anything like that.

This is true and I think it is what happened to me.

DopdBrd
06-19-2008, 09:00 AM
I did mine last night but we got about an inch of rain and sorry my car doesn't see rainy, muddy roads....yes I know, I'm a vagina.

Turnin20s
06-20-2008, 02:49 AM
HAHAHA thats great, I'll go get the hose so you can spray the sand out of your vagina HAHA only kidding. I don't drive my car in the rain either

I'm going to grab a new tranny mount, new torque arm bolts, and new u joints on saturday and see if the vibration is still there. If so I'm going to have the rear wheels rebalanced to see if theres a broken belt or something.

I'll post my progress saturday night, thanks again

Turnin20s
06-22-2008, 10:28 AM
All better, I replaced the steel driveshaft with an aluminum one, set my pinion at -1.5, and put in a stock tranny mount. I did a couple pulls to 125 and it was really smooth.

Thanks for all of the help

SuperSport4life
06-22-2008, 11:53 AM
All better, I replaced the steel driveshaft with an aluminum one, set my pinion at -1.5, and put in a stock tranny mount. I did a couple pulls to 125 and it was really smooth.

Thanks for all of the help

My friend with an LT1 brought my stock alum d/s and his vibration went away im guessin this was the majority of your problem

thechef
06-23-2008, 11:46 AM
so you changed a bunch of things so you dont know which one ACTUALLY cured the problem:bang:

DopdBrd
06-23-2008, 12:09 PM
My car has a new 3.5" chrome moly DS. The only thing I could replace is the tranny mount which may very well be it since I can feel every little vibration in the tranny.

Turnin20s
06-24-2008, 03:48 AM
so you changed a bunch of things so you dont know which one ACTUALLY cured the problem:bang:

Well, I changed the pinion angle before and it did nothing, changed the shaft and tranny mount and all is good. Sorry if your not happy, but I sure am

LM97Z
06-24-2008, 04:45 AM
Just a FWIW, when you accelerate, the nose of the rear goes up, when you let off, it drops back down, so you either have too much downward angle on the nose or a u-joint issue, this will put stress on the pinion bearing & could cause noise.

Turnin20s
06-26-2008, 12:12 PM
Just a FWIW, when you accelerate, the nose of the rear goes up, when you let off, it drops back down, so you either have too much downward angle on the nose or a u-joint issue, this will put stress on the pinion bearing & could cause noise.

Yeah I realize that, but the gears whine all of the time when cruising meaning they are probably not setup correctly. If I let off the gas and let the car decelerate the whine goes away. I figured that the gears would have to be shimmed one way or the other. Mabye not though, but no matter what my pinion angle is the gear whine is the same, I could put my angle at a +10 and the whine would be exactly the same.

Thanks for the help though

thechef
06-26-2008, 11:30 PM
Well, I changed the pinion angle before and it did nothing, changed the shaft and tranny mount and all is good. Sorry if your not happy, but I sure am

i am glad you fixed the problem but like may ppl with this problem you fixed yours but we dont know what was the fix, which keeps ppl guessing still

anyways glad to hear your issue is solved:chug:

Turnin20s
06-29-2008, 02:18 AM
Well if the u joints have been changed a few times and the driveshaft is balanced then the next step would be the tranny mount. I'm probably going to put the poly one back in in the next few days and see if the vibration comes back. I really don't like the rubber bushing, my shifter is all over the place when I accelerate hard, didn't move around nearly as much with the poly mount. But like I said before I really wanted the aluminum shaft anyway and it makes a good excuse to convince the wife to let me spend more money on the car. Besides the stock mount is only like $8 at autozone and takes 20 minutes to change.

I wish everyone else luck, but figured that only changing 2 things and the vibration being gone would narrow down the searching.

sneaky7980
06-29-2008, 10:02 PM
Hell all i did was a brake change and i ended up with a vibe anywhere above 70. I'm ready to just sell the damn thing!

Turnin20s
06-30-2008, 01:38 AM
Hell all i did was a brake change and i ended up with a vibe anywhere above 70. I'm ready to just sell the damn thing!

HAHA I hear you man, I'm ready to get a GTO or something of the like here pretty soon at least then I'd have clearence for exhaust LOL

ElChiefWS602
06-30-2008, 02:27 PM
Those that have the S60 with the Strange chromoly shaft need to check these to things:

1. From discussions with UMI the larger housings (S60 and 9") like an angle of 0 degrees. Use UMI method to set the angle.

2. Check that Strange driveshaft. Mine was an ounce out of balance. Make sure you take it somewhere that can digitally balance it.

My vibration problem was a combination of these 2 things. The driveshaft helped but didn't fix the problem. I had to get that pinion angle dead nuts otherwise I would have change flying out of my cup holder. Took me forever just to get it right.

Good luck.

DopdBrd
06-30-2008, 02:52 PM
Those that have the S60 with the Strange chromoly shaft need to check these to things:

1. From discussions with UMI the larger housings (S60 and 9") like an angle of 0 degrees. Use UMI method to set the angle.

2. Check that Strange driveshaft. Mine was an ounce out of balance. Make sure you take it somewhere that can digitally balance it.

My vibration problem was a combination of these 2 things. The driveshaft helped but didn't fix the problem. I had to get that pinion angle dead nuts otherwise I would have change flying out of my cup holder. Took me forever just to get it right.

Good luck.

Thanks a lot man!!!! I have the pinon angle of mine set at -2 so I bet that is what the problem is. I will go back to 0 today if I can. If that doesn't solve it I will try balancing the DS.

I'm taking the car on a 10 hr ROUNDTRIP travel this weekend and would like to not have to put up with the vibration.

sneaky7980
06-30-2008, 04:38 PM
I'm taking the car on a 10 hr ROUNDTRIP travel this weekend and would like to not have to put up with the vibration.

Good luck!!! Very interested in what the fix is!!!

DopdBrd
06-30-2008, 04:46 PM
FYI I did rotate the driveshaft 180 degrees and it did seem like it helped it some.

DopdBrd
06-30-2008, 05:56 PM
OK well I just adjusted my pinion angle to 0 and guess what........

I THINK IT FIXED IT! Just low speed driving there is no vibration. I will need to take it on the highway to see how it does at speeds above 50.

But like I said, low speed, there is no vibration anymore.

ElChiefWS602
07-01-2008, 01:39 PM
You mentioned you flipped your DS 180 degrees, makes me think the DS may be out slightly. It shouldn't matter which way you put the drivshaft in. My car did the same exact thing, improved when I flipped DS.

I would do like you said and take the car to a higher speed and see if a vibration develops. If it does pull the shaft and get it balanced. Only costs about $50 and a hour of your time.

Let us know how it works out.

Turnin20s
07-02-2008, 12:38 AM
^^Wow $50 for just a balance?? My brother got a driveshaft shortened and balanced and it only cost $75 or $100