Vibration when accelerating

[dorri732]

I have a '92 with 120,000 miles on it. It's recently started having a disturbing vibration at highway speeds when accelerating (or holding speed on a hill). It goes away when coasting (clutch in or out), so it's not a tire out of balance, though that's exactly what it feels like.

Possibly related, sometimes when accelerating at slow speed (10-40ish mph) I hear something rubbing from the rear of the car. I've had it up on a lift to look for evidence of something rubbing, but didn't see anything.

Any ideas for what to check first?

[XfireZ51]

U joints? Do u get a vibe when taking a right or left hander?

[dorri732]

Originally Posted by XfireZ51

U joints? Do u get a vibe when taking a right or left hander?

The rubbing is more noticeable when turning right. The vibration is noticeable at 55mph and up and doesn't seem to change when turning.

Would I be able to feel play in the U-joints if they're causing the problem? I'll have it back home tomorrow and can put it back up on the lift to check.

[XfireZ51]

Had a similar situation only left hander made vibration noticeable. Then one day I drove car and heard what sounded like metal on metal. I had previously thought it may have been rear hub bearing. Inner U joints at diff were Toast. 3 of 4 of them were bad. Can't believe I drove to BG and back with them last year. Car had 113K miles on it.

[sdycke]

I would first check out your drive shaft u-joints. They are best checked with the shaft out of the car and the joints manipulated by hand. Thats the only way to find any subtle binding that will definitely produce vibration but not be detectable by feel when the shaft is bolted up. Use the best u-joints you can afford when replacing bad ones.

[dorri732]

Thanks for the replies. I think I'll just replace them all, looks like they're pretty cheap.

Any brands to avoid? I'll most likely just use whatever my local Autozone or Advance Auto Parts has in stock unless you have any horror stories about them.

[mike100]

Originally Posted by dorri732

Thanks for the replies. I think I'll just replace them all, looks like they're pretty cheap.

Any brands to avoid? I'll most likely just use whatever my local Autozone or Advance Auto Parts has in stock unless you have any horror stories about them.

Oh no- don't even waste your time. I used $10 u-joints on my last vette and they took a lot of effort to seat into the half-shafts.

Went ahead and went 'all in' for the $19 Spicer ones and they went in like butter- didn't even need a tool- just a socket or two and a small hammer. I have 25 lb soft lead bricks I used instead of a table or the concrete floor- it went so much easier- like 10-15 min a side...mainly r&r of the axle assy took the most time.

The cheap ones roll fine, but you will gall the aluminum axles and the next time you go to fit a u-joint...well- it won't fit well most likely.

Spicer- accept nothing else.

[dorri732]

Thanks again. That's the way I'll go then.