So I had my wheels rebalanced yesterday thinking this was my vibration problem. Granted one of them was out of balance, but all is well now.

BUT, my car still vibrates under acceleration, between 20 - 30 MPH, in 2nd or 3rd gear.

Does anyone know what the problem could be? Also, when I get up to 70 mph, the car vibrates alot! But strangly, it vibrates more when coasting as opposed to being under accelaration.

Could my drive shafts be bad? If so, how can I check this?

I am conpletely puzzled and have had this problem for the last 4 months and under two different sets of wheels (19's and OEM). At this point I am confident it has nothing to do with the wheels.

Any help is appreciated. Thanks!!!

 

Most likely transmission shudder. If so, then this is not good.

When is the last time that you had the tranny fluid changed?

What year is your car? What is the mileage? Can you take a picture of the transmission fluid from the dipstick wiped onto a clean white towel - it should be cherry red like cough syrup... if it is black at all, then it is likely worn out.

If the tranny fluid is black then get some new fluid in there. Read up on the threads around here on fluid and how to change it. I would not drive it too much until you stop the shudder - it can significantly damage your transmission if it hasn't already.

 

I have an 06 MT and it has 109k miles on it.

I changed out the transmission fluid around 80k (my guess) with GM Synchromesh Friction Modified.

And I have new fluid on order and will change it out next week. It still doesn't solve the problem of the car shaking at 70 mph too...

 

Cool. Glad that I am wrong about a tranny.

Alxe would be my next guess, but I have no idea how you check them without pulling them. Do you remember hitting a curb or anything?

Good luck.

 

do you have any bends in any of the wheels?

 

No bends, the guy balancing said they looked good. I am going to take it back to him and have him check the axles tomorrow.

 

I had same problem...check your motor mounts. I too thought it was tires, transmission. However, it was motor mounts. Had 2 replaced. Check these before any mechanic sells you a new tranny!!!