Vibration in rear end

kenewagner

Registered User
I installed a newer diffrential with 3.73 gears in my 93 auto. I have a vibration starting at around 50mph and very bad as I get closer to 70 to 80. I have turned the yoke on the drive shaft 1 hole at a time hoping to find a better balance and now have run out of options. The manual saids the companion flange that the yoke bolts on sometimes need to be rotated to acheive balance but removing it to turn it requires resetting the pinion. Has anyone had and solved this problem. There was no vibration with the original diffrential.
 
A Seattle guy brought his 90 SC 5 speed in yesterday for me to swap in my 3.27 rearend and to be sure that there was going to be no vibe, I loosened the trans mount & crossmember bolts, started the engine and test drove the car using all of the gears, then torqued the bolts back up. Which allows the car to seek its own centerline. He left the shop and drove 3 hours to Seattle without a problem. Try that and see if it goes away. Good luck
 
Hey Man

Hey Man,
Did you check your u-joints. It could be your drive shaft. It may sound strange but it also may be your half shafts.
Laterz,
D Rainer
 
Vibration

Each time I moved the yoke one hole I used loctite on the bolts and took it out for a spin. They stayed tight. I know what to loosen on the transmission mount but what crossmember bolts are you refering to? That sounds like a simple solution. As for the drive shaft, I beleive it is OK but I dont know what I would be looking for on the half shafts. Some good ideas. Does anyone else have some input?
 
The cross member under the trans and mounts to the frame has rubber sandwiched around it. It may be overkill on my part, but I just loosen everything that holds the tail of the trans so when you test drive, it can move up/down and side to side and allow to settle to its own center, then tighten it back up. We swapped in new axles because 1 was tossing grease from the CV boot, which could have been part of the vibe at 75 he had before the swap.
Good luck
 
I know that Seattle guy really well.



The car is very smooth. I had a slight vibration after installing my rebuilt engine. It may have been one of the halfshafts Vancouver BC and I changed. He did most all the work but I am still taking a little credit... very little.

It makes sense to do as he says.

I had a great time with my 3.27 gears running down I5. right after the border it goes from 20 to 70 speed limit. I stopped on the start of the freeway (11 pm and no real traffic) nailed it and ran up through the gears. No vibration at all. maybe a little in the front tires. but that was at 70 (70 yeah thats it I was only doing 70) :D
 
diffrential vibration

Thanks guys I will try that. I wont get a chance to work on my car untill saturday. But I will let you know if that does the trick:)
 
I know that Seattle guy really well.

Tell that Seattle guy to post more details on his mods and a snapshot of some engine mods would be nice to.
The credit should go to you, the guy with the wallet and patients to get the jobs done right.

Most of the work on SCs that I do is to keep them on the road so its a real pleasure to work on yours where the objective is to make real improvements in the go-fast depatment and work it from the engine out.

All the best, Good luck
 
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