'92 Vibration Help?

[bwphoto]

I'm driving a 1992 Sport 4x4 5speed with about 185,000. The trans was replaced last February. New starter, batttery, exhaust since then. When I'm driving, the car starts vibrating at random speeds, usually not under 1500 RPM and it also usually starts out at a pretty slight vibration, then gets stronger until it seems to reach a peak. Occasionally it will just stop vibrating for a while then start again. Also, it doesn't happen (or isn't noticeable) at speeds less than 20mph, but does happen at everything above that.

When I press in the clutch, the vibration stops. When I rev the engine with the clutch in, the vibration stays stopped.

Any ideas? It's at the trans shop now but I can't afford to get hosed. I'm planning on doing an engine rebuild during my Christmas break from school, so if I can garage it or drive it very infrequently until then (won't be hard) that would be great.


Thanks for the advice.

Kevin

 

[transmissionguy]

im not 100%sure but have you checked your Universal joints? and also check to see if they tightened up your tranny mount on the cross member. anybody else think this could be part of his problem??

Mike

 

[Rhett]

I agree with mike. Could be the driveline---u-joints/slip yoke.--look into that first anyway, as it's relatively cheap compared to some other things (balljoints, etc.)

 

[DeRocha]

I would agree with the others, it sounds like a drive line problem. Is the drive shaft ok? (not crushed or dented. It should have the balance weights attached... U-joints are another common problem. When where they last replaced? Where does the vibration appear to come from?

 

[bwphoto]

Thanks for the quick replies. It could very well be what you have suggested re: the ball joints and other "front end" stuff. I'm not too familiar with the workings in that area yet (started working on cars 1-2 years ago). When I got new tires they said that 'the front end' needs some work, and that was a few months ago and wanted another $500-600 on top of the $500 I spent on the tires - didn't get it done because it didn't mean immediate doom for my car and I didn't have the $$.

I was so worried it was going to be mechanical or something (could still be, but what you're all saying makes sense.)

Yes, it is coming from the front of the car.

I'll do a search in a minute, but how can I tell for sure if it is ball joints, U-joints, etc...? And is that a repair I can do in a long weekend or is it a major job I should pay to have done? Still learning...

Thanks VERY much.

Kevin

 

[DeRocha]

Ball joints won't be a factor since the problem went away whenever you put the clutch in . Therefore the only parts affected would be:

1) The transmission
- Check it to ensure it has enough fluid.
2) The driveshafts
-make sure they are not crushed / dented.
-make sure the balance weights( like wheel weights but for the drive shaft). have NOT been knocked off
3) The U-joints.
- There should be no "play" in a u-joint's movement. The joint should be tight, but not frozen.
My bet would be here since they are the weak link in the drive line. Most are sealed and cannot be greased. If they are original then @ 185K they are due to be replaced...

 

[bwphoto]

The mechanic called and said it was the U joints. $140 for everything. Sound good? I'll probably do it because he said it would be risky to drive on them and to fix anything on a car for less than $500 seems like a fair deal to me these days.

Thanks for all your help - when he replaces them I'll post whether it worked or not.

Kevin

 

[DeRocha]

$140 seams a little high, but I did them myself so I wouldn't know what a shop would charge for labor. If you don't work on cars alot then this cost would appear to be slightly high (depends on how many u-joints they are goint to replace. The rear drive shaft has two . while the front drive line has 5 after the "T" case. Whatever you do insist on Heavy duty U-joints. Std duty versions cost $8 ea while heavy duty go for $14. Remember its the labor that really cost not the parts.

Replacing U-joints is not the big of a deal. Just as an overview You would need to obtain a "U" joint tool at Autozone or some other parts place. Most stores rent them for free so you will buy the parts to do it yourself. This tool is required and looks like a giant "C" clamp. It is used to force one end of the Joint out so the bearing cap on the other side can be removed and the process repeated on the other side. This tool is quick and easy if you have access to an impact gun.

 

[DeRocha]

This is the step by step procedure for replacing the U-joints.

U-Joint replacement procedure