Turnin20s

iTrader: (12)

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

iTrader: (25)

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

Turnin20s

iTrader: (12)

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

iTrader: (25)

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

iTrader: (12)

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

iTrader: (11)

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

iTrader: (3)

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

iTrader: (12)

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

iTrader: (3)

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

iTrader: (2)

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

iTrader: (3)

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

iTrader: (9)

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

iTrader: (12)

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 Otherwise I'd throw it back in and see if the vibration goes away

Turnin20s

iTrader: (12)

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

iTrader: (10)

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

iTrader: (6)

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

iTrader: (12)

^^ 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

iTrader: (25)

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

iTrader: (6)

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

iTrader: (25)

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.