[Zeder]

Hello again!
I have been driving my 350ci Cutlass wagon converted to a 5speed for a week now. Everything seems to be ok with the exception of a driveline vibration under heavy acceleration. I never had this issue before I swapped out the 2004R trans for a T5. So I am pretty sure its not in the rearend. I did notice that when I put the newly shortened and balance driveshaft back into the car, had to shorten it by 3 inches, I could wiggle the driveshaft up and down on the axis of u-joint cups that bolt to the rearend. It would move about 0.025in or so. The centre of the u-joint would move between the cups. This u-joint uses the c-clips inboard the bearing cups to centre it. It's like the cups or one cup is not getting pushed onto the u-joint all the way. But the c-clips are in there respective slots. Has anybody seen this before? I installed heavy duty u-joints when I did the 2004r install adout 10k miles ago. The car originally had a th350 in it. The inside of the u-joints looked great, and they have lots of grease! I am wondering if this vibration is from this little bit of play? By the way it is fine when I am just crusing around, its only noticable under acceleration. It also get worse the faster I accelerate. Any comments?
Cheers,
Zeder

 

[Triaged]

It shounds like you have a different output yoke that is made for a different u-joint. Of course the vibe is from the slop! It is trying to tell you something is wrong and you shouldn't drive it till you fix it. NAPA often has "bastard" u-joints.

 

[advanced design]

Yes, the culprit is most likely the U-joint with the slop. If the yoke is a different one the u-joint is not the correct size for it. Find a correct sized one and replace it right away.

NAPA may well have what you need. Also, Dennys Driveshafts is a good source for unusual joints.

Good luck.