I recently replaced my stock engine mounts with RS engine mounts. We also installed a Rothsport reinforced engine carrier mount at the same time.

Car has a brand new, rebuilt transmission that was installed about two years ago and did not exhibit this sound before. Car is a C2 and does not have an LSD.

I’m now noticing a whine in 5th gear and possibly a VERY faint whine in 4th gear. It’s not speed dependent.

Any thoughts as to what’s causing this?

 

Sure, you might be getting some additional NVH, did you change shifter too?

 

Thanks, @Spyerx. Car came with an RS lever. Was going to replace it with a golden rod and FD SSK next.

I skipped an aftermarket transmission mount since I’ve heard there are more NVH issues there.

 

So are your transmission mounts still the original? I just replaced mine and transmission noise is noticeable less with the new mounts. The old ones didn't look that bad but the rubber was gone.

 

Thanks, @cjoenck — I went through the old records, and I don’t see a record of replacement. If so, then they’re 29 years and 170k+ miles long in the tooth. Definitely a candidate for further inspection.

 

Just do the function first insert with the old transmission mount. Pair that with a new transmission mount if you want a stiffer and crisper shifting feel. Engine carrier and motor mounts are going to tighten the car up for sure.