When i accelerate on 2nd gear around 1500-3000 rpm, car shakes really bad and 3rd gear as well. Currently i took off wheel spacer on front because steering wheel was shaking really bad and once i took off spacer, it’s all gone but it’s different symptom though. It only happens on 2nd & 3rd gear while accelerating.
Steering wheel is fine but the whole car shakes though.

 

Engine/Transmission mounts.

 

I’m planning to install powerflex bushing. Do you think i have to replace mount when installing powerflex bushing?

 

That was just a suggestion, too many variable to diagnose over the forum. What year/model car, how many miles, what is the history,have you had anyone check the mounts/suspension? When you say PowerFlex, I assume you mean Lower Control Arm Bushings, that would be a start. Before you start replacing parts, I would start by getting someone to diagnose your issue.

 

it's 2003 mini cooper s with 90k miles. i've replaced upper engine mount and lower engine mount with powerflex bushings and transmission mount with powerflex bushings. I know powerflex bushings makes vibration a lot more than Stock one. It had same problem when i had a oem engine mount on it. i don't really think that it matters with powerflex. technician said that engine mount and suspension looked okay.
hopefully it is not related to transmission..

 

Updated: I went to the mini cooper service shop and the owner who owns 3 of R53 testdroved my car and i was sitting on passenger side and after driving a few blocks away from the shop, he said it's because of Cv axle. he seemed really confident about what he said. He didn't even lift the car up since he was working on other cars. the thing is i've replaced both driver's side (replaced twice because one of them was defective) (2 months ago) & passenger side (a year ago). He didn't mention which side was problem. my concern is why it keeps happening and what can cause it keeps breaking in? does Transmission Ouput Shaft Seal cause this problem? i think something that holds cv axle doesn't last long. Please advise.

 

I have an 05 R50 that had the exact same issues. Under power in 2nd and 3rd gear brought about a vibration in the driveline. Turned out to be the passenger side CV axle. Once I swapped it, the vibration went away. However (and I think they are related), shortly afterwards, the transmission started leaking from the driver's side seal. I replaced the seals, a couple of times, only to find out that the problem was the diff bearings were worn and allowing the differential to "wobble".

My R50 now has a 6 speed in it.

 

Is the car lowered / slammed? Lowering the car too much puts stress on the CV axles and causes them to fail.