Vibration at 50mph+ off throttle, pinion angle?
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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 $$ if it's not going to fix the vibration.
I bought a new yoke and ujoint, and had the driveshaft balanced.
I've tried four different pinion angles (slight changes) by putting washers behind the top and/or bottom of the torque arm mount (it's a seperate piece from the rear end) and it has made no difference.
I've noticed that the rear is not quite centered though (left and right) is that going to be my problem? It's probably 1/2" tops over towards the driver's side. I know an adjustable panhard rod can fix this, but I don't want to spend the $$ if it's not going to fix the vibration.
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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
Hope this helps
Jon
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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?
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?
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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.
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.
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"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.
Ben T.
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Originally Posted by Studytime
"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.
Ben T.