# GTO's got the Shakes!



## KyleGT05usmc (Feb 28, 2009)

OK. So I missed a gear with my new shifter, missed going to 6th from 5th, went into 4th(over 100mph at least, was gonna coast out 6th), I noticed pretty fast but still jumped the back wheels and revved her up pretty high. 
Ever since I've got the shakes. 
I notice most going from a stop in 1st gear(normal accel) I get a bouncy/shake that feels like its in the rear suspension?

I first thought maybe it was the drive shaft bushing between the 2 parts. But it feels further back than that and its not constant as a driveshaft issue, I dont feel it so much in the shifter as I do behind my chair. Also, say I'm cruising in 3rd and I add some throttle I can feel some shifting around back there. Or if I down shift I feel whats seems to be an opposite shifting. Its pretty much only with a shift in the weight of the car. And only straight lines. And as stated its not constant while smooth riding. 


I crawled around and tried to inspect some bushings but I gotta get her on a lift to get a good look. Anyone have a good idea which bushing/mount this might be??? 

Thanks. :cheers


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## KyleGT05usmc (Feb 28, 2009)

been reading around the forums. found something about a 'driveline coupler using crush bushings' to be frank, wtf is that???
http://www.gtoforum.com/f39/vibration-under-acceleration-please-help-25074/


also reading about the X frame bushings, ive heard before the stock fluid filled ones suck, where can i get some solid ones? marylandspeed?
http://www.gtoforum.com/f39/clunking-rear-end-when-shifting-hard-21716/


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## Justice (Oct 9, 2005)

This nasty rubber disc is the coupler. You might have torn it. The pic is the rear coupler, the front is identical.


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## KyleGT05usmc (Feb 28, 2009)

Ill have to check that out, need a dang mirror on a stick lol. But wouldnt that send a more constant bounce/wobble being in constant motion?

I mean i can def see that having gone, guessing the trans was put under tremendous stress @ that load/rpm.


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## Justice (Oct 9, 2005)

Well, your issue may be something else, but you were asking about the coupler so I put up a pic. I started to get vibration at 50+mph, plus if I got on it from a stop, the back end just felt like it was bouncing all over the place. 

As for the "thunk" under hard shift, there is a TSB on that. You should google "Thunk in the trunk". There is also a dedicated thread to TSB's over on LS1GTO.com.

You probably won't be able to get this covered under warranty, but it doesn't hurt to try anyway. Some service managers are awesome, while other are just pricks. Luck of the draw.


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## KyleGT05usmc (Feb 28, 2009)

Thanks man, hopefully can get on a lift soon. You know a source to get those parts? And what about the x frame bushings?


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## GTOJer (Oct 20, 2006)

Thunk in the trunk only applied to early 04s. It was a rubber shim that was left out on the rear x-member bushing. Had it, had it fixed (warranty), replaced it with poly.

Liquid filled bushing is the front radius rod bushing. Left over from the 6 cyl version of the Monaro. Should be replaced.

You are a marine. Get to your hobby shop and get it on a lift before you hurt your car more. With what you have described, you tore the rear rubber bushing in the driveline.

You don't want to do the work? Bring it up to me in Chesapeake.


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## jpalamar (Jul 22, 2008)

^ I bet mine has that same issue. I just assumed it was my rear going bad but never looked into it. It has started clunking when I get on and off the gas, usually at low speed only though. It might be happening at higher speed but with my exhaust and everything I don't notice it.


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## GTOJer (Oct 20, 2006)

Jay,
Could also be play in the CVs. I said that about the OP because his was an isolated violent event. When you put the car on jackstands, make sure the car is in gear and parking brake off, then try to rotate the tires in a quick back and forth motion while you are under there. Problem should present itself.


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## KyleGT05usmc (Feb 28, 2009)

Haha you havent been to Lejeune's hobby shop lately! Good luck finding a bay and hopefully the jackass wont say your car is too low... 

Im looking around for those bushings, i want to replace the troublesome ones either way but im not sure which are which BMR Fabrication Inc.

Havent located the coupler yet...


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## KyleGT05usmc (Feb 28, 2009)

https://secure.merlinsoftware.com.au/peddersusa/default.aspx?ProdCode=GTOST1 ???

this kit seems to include the front radius rod bush, the x frame bushings, the bushing on the back of the diff housing... anyone have a link to where to find torque specs on these parts so if i DIY i dont over/under tighten


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## 87GN06GTO07IRL (Aug 10, 2009)

You should also look for twisted axle stubs. Down shifting to forth at over a hundred could do that easily.


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## KyleGT05usmc (Feb 28, 2009)

Ive peeked under the car on a jack, the drive shaft coupling didnt appear to be torn. i tried to take it to get on a lift and they wouldnt let me put it on because the front bumper cover wouldnt clear and they wont use boards. 

i was in the rain and had to come to a sudden stop the other day and def felt those front stock bushings give out, holy ****. so im thinking of getting the pedders street 1 kit and putting those on. 

well i found the bumper is rather easy to take off so ill take it off to get it on the lift soon and take the camera under with me to sort this out


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## KyleGT05usmc (Feb 28, 2009)

well i got a hold of a shop that will let me go on the lift for like $20 so im going tomorrow to check it out. hopefully i can get it fixed fast because this weekend looks good for track to be open =]


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## KyleGT05usmc (Feb 28, 2009)

Well after some crawling around found its the drive shaft carrier bushing, (one of the first things i thought might i add lol) 

anyways the shop was trying to hunt one down and couldnt find one so they started talking about 1 peices but i dont have that money for a drive shaft. 

so, any one know where to find these bushings? im looking at the moment but coming up empty handed. ..:shutme


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## tblentrprz (Mar 30, 2010)

Any success on finding center bearing?

I've got an '05 coming my way with a shudder/vibration complaint under hard acceleration. Touched base with GM dealer to get a feel for part availability. Center bearing (item #15) not available. Check out Pontiac 2005GTOBRAKES-REAR AXLE-PROPELLER SHAFT-WHEELS2004-2006 V PROP SHAFTCar parts for your Buick, Cadillac, Chevrolet, Hummer, Light Truck, Oldsmobile, Pontiac, and more!

Complete shaft assy list $1479 (includes both coupler kits - list $274 ea.)

I hear there is a single piece shaft out there as aftermarket replacement? Anyone using one? Pros/cons? Recommended supplier? Owner may keep the car if we can work out this cars short comings especially after the dealer has created a few issues while servicing the vehicle under warranty. Anyway...

Many thanks for feedback!


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## KyleGT05usmc (Feb 28, 2009)

They dont sell just the carrier. And to buy the whole thing from GM is wayyyy expensive. But pretty much everytime ive looked, i have been able to find a used driveshaft. the one i got has held up really well for me so far. i would suggest that route. good luck on it and ill keep my eyes peeled as well.


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