Hard shifts and rear diff clunk

So I got the go ahead from Dave at cryotune to get some regular and aggressive driving in for about a week. So today getting on the highway after work I was next to a z4m and was keeping pace just to be obnoxious. Well shifting from second to third at redline I hear the rear diff clunk. It was certainly an aggressive shift.

 

I have some rear diff inserts to install which will certainly help but I want to make sure I don't shatter my tranny. Is the rear diff clunk from poor shifting and shock loading? Or will it happen on worn out bushings even on an OK shift? I certainly didn't have any jerking through the body, just the clunk, but I did dump the clutch and floor it to try to keep up with a car I'll never be able to keep up with.

 

Stage 1 tune on all oe parts doing 16ish psi boost I think

Rebuilt upgraded jmp vf-46

Group n motor and trans mounts

Kartboy poly trans bushings

 

 

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I've always had a little more driveline shock than I think is normal, but have never been able to figure out exactly what. I have poly differential mount bushings for the rear and I still get that little jerkyness when I go into the next gear up and try to accelerate. Many threads recently have been asking questions about driveshafts and something tells me that my high-mileage car is ready for one. Guess others can chime in.

In theory it should be bushings.

 

My wagon started doing it a while back, may be last Fall.

Yea I figure they are worn out. Everything else is. I just wanted to check it's not a "if you shift right you won't get that noise" sorta issue.

 

Maybe next year I can drop and restore the sub frame and press in nice poly bushings everywhere.

 

 

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Every bushing relevant to my rear diff has been replaced and I still get some clunk. Something tells me that the OEM DMF would have perfected quite a lot of it.

 

For the record I would NOT recommend poly bushings for the rear diff. All but the rear diff support bushing on my car has been replaced with poly and the NVH difference is pretty annoying. The support I had Surgeline replace with OEM. I wish I had just used OEM for everything because the whine from the diff is, IMO, not characteristic of this car and my car is pretty much as loud as a WRX on the inside now. Maybe it wouldn’t bother you, but it’s something to consider.

I drove my civic like two days before it got wrecked and thought to myself "I thought this thing had gotten loud?"

 

I just don't want it to keep smacking the bottom of the car. I also have a smfw so maybe that's part of it as well. At the moment every bushing on my car is shot. So it'll go up either way. I find the transmission whine is obnoxious sometimes.

 

Yea I honestly don't think I'll know what level of nvh will bother me until I get there. At the moment I'd like to get the nameless mufflers and coil overs so I'm expecting my noise to go way up.

 

 

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