So I noticed some weird noises on down shifts.

I always try to re-match on down shifts. So as I push in the clutch rev the motor up to go into the lower gear, and I get a grinding/rattling noise as the revs come up, and the shifter goes into 2nd gear from 3rd.

So I don't let the clutch out, and coast along. With the shifter in 2nd still, I rev the motor with the clutch still pushed in, and as the engine reaches 3800-4000RPM, I get a loud grinding and shuddering from the transmission, and the car starts to accelerate very slowly. Seems to get worse as the revs go higher, but then goes away as the revs come down.

The weird part is I couldn't get it to do it in any other gears, and I couldn't get it to always duplicate even in 2nd.

I already have a new transmission on the way, but I don't want to install it till I figure this out.

Thanks for any thoughts.

I'm running ls7 clutch with aluminum flywheel, and updated hydraulics.

 

On further investigation, it turns out it does it in all gears. After replacing 2 pilot bearings, I put in a pilot bushing about 20,000 miles ago could that be the problem?

 

Might be a sloppy input shaft due to excessive mainshaft clearance. Mine loosened up and badly wore out the pilot bushing and the thing growled and rumbled between shifts plus put off a funky vibe. Again this is only between shifts.

I recently rebuilt it and set the mainshaft clearance to .001".

 

I would agree with the above. Potentially worn out bearings.