silverTA2002

iTrader: (1)

I installed a 9" and since I've had it, I've had a vibration at 50mph plus. An important part to note is that the vibration is twice as bad when coasting off throttle than when on throttle.

I bought a new yoke and ujoint, and had the driveshaft balanced.

I've tried four different pinion angles (slight changes) by putting washers behind the top and/or bottom of the torque arm mount (it's a seperate piece from the rear end) and it has made no difference.

I've noticed that the rear is not quite centered though (left and right) is that going to be my problem? It's probably 1/2" tops over towards the driver's side. I know an adjustable panhard rod can fix this, but I don't want to spend the $$ if it's not going to fix the vibration.

slowrollin93

iTrader: (7)

The drive shaft sitting over to the side is not going to make it vibrate its not bad for it either. I would put it on jackstands or a lift and have some one take it up past 50 and see if you can see were the vibration is worse at or if you can see anything wobbling. I had to do that with my truck turned out my yoke was bent. Could it be possible that you bent the output shaft on the transmission? That was one of the things i checked when mine was vibrating, pulled the drive shaft and watched the output shaft to see if it had any wobble to it.

Hope this helps
Jon

silverTA2002

iTrader: (1)

Well, I went ahead and bought an adjustable panhard rod.

I centered the rear on the car, and the vibration got a little better, but it's still there.

Then I tried centering the rear closer to on the driveshaft, but I can't tell if it got any better. I don't know.

Anyone know if the rear should be centered on the car or on the driveshaft to remove vibration?

35th SS

iTrader: (2)

where is your pinion angle@ right now?had a slight vibration on a decel.set my pinion angle@ -2 dergees. vibration all gone.

silverTA2002

iTrader: (1)

I haven't been able to measure the exact angle yet (don't have a tool). But I've changed it from slightly positive to slightly negative and 2 places in between. The vibration hasn't really changed.

I also started off with the rear being off to the driver's side 1/2 an inch, then centered, then off to the right 1/2 an inch (which was almost centered on the driveshaft). Vibration is still there.

Centering the rear on the car, and going slighty negative on the pinion angle seems to have made the vibration slightly better, but it may just be in my head.

silverTA2002

iTrader: (1)

I just need to know if the left to right pinion angle matters or if it's just up and down.

35th SS

iTrader: (2)

try goin -2 or 3degrees the most on your pinion angle.measured mine on the flat spot next to the bolts that holds the t/a on the center rear.

silverTA2002

iTrader: (1)

Anyone know about left to right pinion angle?

Studytime

iTrader: (15)

"Compound" pinion angle is never a good idea. It needs to be inline with the driveshaft. That's a function of the build of your 9". If it's inline with the driveshaft it should also be in the center of the car.


Ben T.

silverTA2002

iTrader: (1)

And if it isn't quite? What's more important, inline with the DS or the car?

Studytime

iTrader: (15)

If your rearend is built right, both should be largely inline.

Ben T.

silverTA2002

iTrader: (1)

It's pretty close, but not dead on as far as I can tell. Probably less than an inch off of being centered on the DS when it's centered on the car.

oange ss

iTrader: (50)

find the problem ?

cowboysfan

wondering same here.

did you fix it??