Tire flaw, balance or CV shaft?

[buck91]

Any tips to help me differentiate a vibration I'm experiencing in a 2001 Olds Aurora? I would like to determine whether the tires need replaced, balances or if my other half shaft is finally going out (inner CV joint).

It vibrates during acceleration most obvious between 40-50mph with body shake and steering wheel shake. Does not vibrate during coasting or braking. Some other minor vibes here and there as the car is older, but nothing else this concerning.

Some background, the driver inner cv joint was puking grease for a long time, replaced it this year and the vibration got MUCH better, but is still present. Passenger side inner CV was fine until recently when I noticed some grease puking from the inner (larger) boot clamp with no tears or boot failure found on inspection. All wheelbearings are fairly new. Tires are used and were installed without rebalancing, but like I said the vibration is acceleration dependent and is manifest as a side-to-side type vibration.

This car is kinda of its last legs and we are just trying to get as many miles as we can out of it before it becomes necessary to replace it with something more reliable, so I'm trying to replace stuff "just because" but if its clearly a certain part on the way out thats fine. Car sees probably 500+ miles weekly.

 

[HangFire]

Lift front end, turn wheels by hand and check for slop in CV joints. Have someone turn the steering wheel and check if wheels move in unison.

Rotate tires and see if the problem moves around.

 

[Lubener]

I would believe tires would vibrate during acceleration or coasting at the same speed. I would look at the half shafts.

 

[punisher]

Inner CV joint most likely cause. Distant second is a broken/loose engine mount allowing engine to rotate/lift during accel putting the inner CV at too high an angle relative to the half shaft.

 

[buck91]

Thanks for the suggestions so far, I too am leaning towards inner cv joint. As for the engine mount suggestion, visually they all look intact, but the engine does move quite a bit if the car is in park and I manually push the car back/forth. Not really sure what to look for there.

 

[HangFire]

Originally Posted By: buck91
Thanks for the suggestions so far, I too am leaning towards inner cv joint. As for the engine mount suggestion, visually they all look intact, but the engine does move quite a bit if the car is in park and I manually push the car back/forth. Not really sure what to look for there.


Pop the hood, start the car and put the parking break on hard. Have someone else rev the engine slightly in D and R while standing on the brakes and you are watching the engine and the mounts. If a mount is bad you'll probably see some startling movement.