Vibration
 

First off, yes, I have searched and searched and im still not getting any where. I installed a moser 9 in my ws6. I had a stock tq arm on for a short period of time and had a horrible vibration so I installed a adjustable measured the d/s angle and rear angle and what not, then adjusted the tq arm accordingly.

When I first start driving the car its smooth till about 65/70. Thats when the vibration is fairly noticable but tolerable. Once I slow down I get a pretty bad vibration at 40+. This vibration is kind of a solid feeling? Its obviously because everything isn't spinning as fast but its bad.

My rear setup is a moser 9 housing with a ford nodular center 3.55 gears and a stock ford posi, 1330 LONG yoke, and a stock length chromemoly d/s. Suspension wise I have a non adjustable panhard bar, adjustable tq arm, adjustable lca's(which i recently adjusted, and kinda helped do away with some vibration until i hit higher speeds).

Also, when i hit a bump I get a loud clunk sound from the passenger side rear of the car even if its a tiny one. This started happening after the 9inch install as well. I'm at a loss with all of this.

Did you look at your tranny mount? Also do you have a DS loop? If so check its not wacking the bottom.

JW :D

Check your torque arm clearance to trans tunnel, usually they smack the car there.

Whats the pinion angle set at?

I'll climb under tomorrow and make sure
-2....thats what it came out to after I subtracted the pinion angle from driveshaft angle

The torque arm mount is most likely hitting the trans tunnel where it connects to the rear. Have you done the obvious like tire balance and check the u joints for binding? Is there excessive gear wine? Everything purchased new or some used? Its only speed related, not rpm related?

The torque arm mount is hitting the trans tunnel so thats probably my clunk sound. I rechecked the tq arm angle it was at 0 for some reason so I adjusted to -2. Vibration got slightly better. How ever I had Wolfblitz in the car with me and even he noticed after I got on it the vibration got worse at lower speeds. The gears do whine a little, and the center section is used. I did notice that the ujoint straps on the yoke one side is bolted down more that the other...would that put an angle on the ujoint? Also since I have a stock length d/s and I used a long yoke, could that be causing a vibration too?

I checked the trans mount, and its tight not loose at all.

Aluminum or steel d/s?

Up above he states it's a stock length chromemoly.

Why the long yoke? And can you get a pic of the straps? If that is causing one of the u-joint caps to not seat properly then that may be the source of your issue. Oddly enough you can get 1330 straps in the Help! section of Pep Boys.

I went with the long yoke to make up for the slack because the 9" sits an inch back compared to the 10 bolt, right? I have the right straps, it just appears I tightened one more than the other.

Tighten it down and see where that leaves you.

I took the straps off and reinstalled them making sure they were equally threaded, no difference. Im not sure what else i can check.......almost makes me wanna go back to the 10 bolt. I did notice that the vibrations suck while driving, but they are even worse on decel.

I'd look towards the rear's internals, be it pinion or carrier bearings, causing the vibration.

I pulled the housing out had it checked out and had the back lash checked everything is ok inside but it still vibrates

Did you set the pinion angle with the suspension loaded?

Also, the pinion angle is supposed to be set relative to the engine, not the ground. I was able to use the passenger side cylinder head front surface as a reference point, and set my pinion angle to 1 degree down relative to the angle of the motor.

Yup

So measure the angle of the motor?

Your exhaust system could also be causing the vibrations. Use a rubber mallet and tap the pipes, cats and muffler when hot and cold. I found a bad exhaust mount once causing the vibration in my car. I was blaming everything from the trans to the rear trying to find the problem.