Hi everyone, 996 Newbie here. I bought this car a year ago and have enjoyed almost 5k miles. When I first got the car, it developed the dreaded flashing D4 trans lights. Had the codes pulled and it turned out be the NSS. Replaced that, did a fluid and filter service and everything back to normal. However, the tranny has two issues that bother me. First one is a hard shift to reverse when cold as in first start. If I let it warm up to 160+, not bad and after driving for a while non existent issue. Temp sensor?? Shift to forward when stone cold is smoothe.
Second issue is gear/bearing noise that is more noticeable in manual mode that auto, expecially on deceleration from all gears. The noise does not change with engine RPM so it is final drive related. Possible bad pinion bearing? I have not checked/changed the dif oil yet. I have asked around and nobody seems to know anything about these transmissions. I am in South Florida if anyone has any recommendations.

 

You must be talking to the wrong people, these trannys are common. How many miles? Have the fluids ever been changed?

 

Fluids and filter changed same time as the NSS, about 3500 miles ago.

 

Oh, bought with 51K miles, now at 55K.

 

I have a '01 C2 tip as well and it does shift harder in cold (though i think thats common in many cars).

One fix i made that helped overall was a new gas cap. There was a slight vacuum leak that was causing performance issues similar to which you state. Changed gas cap and it went away. Simple but sometimes the solution often is....