# Driveshaft movement



## taylorjones_11 (Jun 19, 2013)

Hey everyone, I'm new on the GTO forum. I have searched all forums looking for an answer to this problem but have not found anything that was exactly the same as my problem. I installed a 1 piece aluminum driveshaft in my GTO about 6 months ago, because the carrier bearing in the OEM one was shot. For a while after I installed it, the drivetrain felt super stiff, and there was no slack at all. I loved the way it drove, no clunking, or play in the drivetrain. I slowly started to notice some slack coming into the drivetrain, and now it seems almost as bad as whenever I had the stock two piece in it. Also I had the car on a lift the other day and moved the driveshaft in an up and down motion and there was a little play vertical. None horizontal at all, but it would move up and down slightly. I've also noticed a bumping noise almost like a U Joint on an old style car is about to go out whenever cruising around holding a steady rpm. For example, 3rd gear around 25mph, holding rpm at around 2 grand occasionally hearing a thud, from under the car. Does it in every gear, but not all the time that I notice. Someone riding around in the back seat of my car can hear it much better than the driver can. Can anyone help?


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## svede1212 (Nov 1, 2005)

Are you using the adapter plate? I've had issue with the bolts loosening up. The Drive Shaft Shop sent me a new plate along with new bolts with nuts to put on the back side.


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## taylorjones_11 (Jun 19, 2013)

Last time I was under the car, I checked the bolts that were accessible and they were still tight. I used loctite as suggested in the install kit. When I spin the driveshaft back and forth there's no slack between the plate and the rear differential three finger type flange. (sorry about the technical terms I'm not very educated in driveline terminology) The place i'm getting the vertical movement is up front where the slip yoke goes into the tranny. The rear just seems like slop. I'm about to do a rear diff fluid change that should help if what i've been reading is true. Still kind of stuck without an answer for the vertical movement I'm getting


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## aardennc (Jan 27, 2013)

hey i know that the u-joints need to be in the same orientation. if yours came already assemble, this may not be an issue. i assembled one on my own years ago and didn't get them right, consequently there was lots of vibration. other than that you may need an expert to sort it out.


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## taylorjones_11 (Jun 19, 2013)

Thanks for the reply, but yes it came assembled. No vibration either. Just feels sloppy when on and off the gas in the same gear. Also sloppy shifts. Cant seem to get it right even after having the car for nearly a year now. I used to not have a problem, but recently its getting harder to get smooth shifts, along with all I posted above.


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