dandaman19

When in sport mode at 3k+ RPM, there is a noticeable bump or jolt when I suddenly lift off throttle. It seems like the transmission is not tightly engaged to the car. Is this a bad transmission mount or something else?

idylldon

Motor mounts are a definite other possibility. The quick change in torque load will cause a loud bump if they're worn.

Cheers,
--
Don

dandaman19

Thanks don. I changed mounts and it didn’t fix it.

Bruce In Philly

2009 C2S 180k miles

There is what it could be, and what is most likely.

It could be a lateral control arm in the rear (I can't think of anything as bad as getting a control arm in the rear). If it is, you should feel the car steer slightly at high speed when you take your foot off the gas.

It could be a bad CV joint on a rear axle. You should be able to make it clunk by hitting the gas on and off. For this, check the CV boots (2 each shaft) for tares. Dirt collects in the grease and grinds them away.

It could be the transmission mount. This is one of the three mounts holding your drive train to the car. I don't know how to test for this.

It could be wheel lugs are loose on a wheel.

Let us know what you find.

Peace
Bruce in Philly (now Atlanta)

dandaman19

I can make it happen over and over by getting on and off throttle. CV makes sense. I’ll get moving on that and report back.

thanks-a-million.