OMFG please help, mysterious and persistant vibration in drivetrain

Jul 25, 2005 3 Replies
M

This problem has been lingering for almost 9 months now and nobody seems to know the answer, or they just tell me "its a 20 year old car, what do you expect?"



I'm aware its 20 years old. I'm just trying to make it right again.



Its a 1985 Corolla, RWD, SR5. I just had the driveshaft rebuilt. Here ar e the symptoms I'm getting:


  1. Rumbling noise and vibration from about 30 MPH to 65 MPH - independant of gear or engine speed. Just as bad in neutral as in any gear
  2. Had a stethescope hooked up to it, very little vibration coming from the support bearing itself, and a significant amount coming from the rear end and transmission.
  3. The rumbling and vibration ONLY STARTED when the driveshaft was replaced.

My question is this - could the tranny or driveshaft been ruined by the installation? Could the driveshaft still be out of balance, even though the reading is low on the support bearing? My mechanic said he was sure that the shafts were in phase with each other. How can I check this?



Maybe I just have a s***ty driveshaft?



Any responses are appreciated. I'm sick of getting a headache whereever I drive.


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M

To be in phase the u-joints need to be at the same place on both ends of the driveshaft. So if you put the shaft on the ground and have the u-joint at one end flat with the ground, the other one has to be the same. On some driveshafts, there is a slip joint so the u-joints can be off a spline or even off 90 degrees so when one end is flat with the ground, the other joint is pointing to the sky.

Even if the joints are lined up and the driveshaft has the spline split, they could be 180 off. That means you pull the driveshaft apart and rotate one end half around and put it back on.

The shop was 'supposed' to mark this before it came apart so they could put it back together the right way.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Masospaghetti wrote:

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M

Thanks for the responses. The problem is fixed!

The culprit? OUT OF BALANCE, after all that. The shop we had brought it to must have lied or done it wrong, because I went to another shop, got a hose clamp slapped on, and ta-da!

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