# Vibration under acceleration?? Please Help!!



## RedGoat_05 (Jan 13, 2010)

I had my car to the dealership a couple weeks ago to have the tailshaft housing replaced. Ever since then I noticed a vibration in the shifter and you can feel it in the whole car. Its mostly in 3rd and 4th under heavy acceleration. I'm wondering if the tranny could be lose or if it is something in the driveshaft. Has anyone had that before?? Please help!!


----------



## Justice (Oct 9, 2005)

The driveline coupler uses crush sleeve type lock nuts. These lock nuts can only be torqued ONCE. If they are ever removed, they have to be replaced with new ones. I've only found these in a bolt kit for the coupler and they retail for about $85 for a bolt and nut set. 

I had a dealer do a clutch job on my GTO, and re-used the nuts. The rear coupler started vibrating and damaged the front pinion deal and bearing on my diff. They denied they caused the damage. I'm in need of a $3500 rear end in my car because 3 lock nuts were re-used.


----------



## MTUGTO (Jan 22, 2010)

Daymm that awful. Where exactly are these luck nuts at? Outside of the donuts on the driveshaft?


----------



## Justice (Oct 9, 2005)

MTUGTO said:


> Daymm that awful. Where exactly are these luck nuts at? Outside of the donuts on the driveshaft?


Kinda, yes. There is a step by step article on replacing a clutch on the High Performance Pontiac website. Some good pics there. Google should be able to turn up some good pics for you.


----------



## AlaGreyGoat (Jul 6, 2006)

Check eBay or contact Seller: fparts if you need a rearend.
I have two spares in my basement I got for less than $200
each.
Also, there have been tons of people who have reused
these nuts and bolt without any problems.

Larry


----------



## Justice (Oct 9, 2005)

And that's great that they can re-used a damaged nut and have no ill effects. I wasn't even aware of those type of lock nuts being used until I had the car in for a rear area vibration at speed. Then it was pointed out to me that I had a loose connection at the coupler and it had damaged the front pinion seal and bearing.

And thank you for the information about rear's on ebay! I will definitely be looking into that! I only quoted $3500 because that's what the dealer shop supervisor had told me. I knew I could get them cheaper elsewhere... it was the sting of the dealer telling me that the damage was caused by them, and they weren't going to fix it that irked me.


----------



## AlaGreyGoat (Jul 6, 2006)

Almost all the nuts and bolts on the GTO's suspension and undercarriage are the TTY type,
for one use only. I don't understand the loose bolts on the rubber donut coupling causing the
pinion seal and bearing failure. I've seen the rubber coupling tear at the metal thru tubes and
vibrate, but never cause this failure. Now, if someone loosened or changed the yoke on the
differential and didn't replace that crush tube, well that's another story.

Larry


----------



## bwiest (Nov 30, 2008)

I would recommend always replacing the bolts. It might cost a bit more, but bolts are only ever designed to be loaded once if you intend it to keep the strength characteristics of that bolt. Any subsequent re-use significantly reduces the overall capabilities of any bolt or nut. Just my $0.02


----------



## Gotagoat (Jan 6, 2006)

Good thread, good info; but, damn, Justice, your avatar is distracting. (Don't change it though.)


----------



## joesykora (Dec 14, 2010)

I had an issue with vibration on acceleration. The vibration started at roughly 20 MPH and got more violent under heavy acceleration. This would happen in all gears. The vibration would decrease while costing in neutral or spooling down in gear. Found out that I was missing a bolt in the front joint of the drive shaft. I had a new Centerforce dual friction clutch installed 4K miles previously to this issue. Hope this helps.


----------

