1999 C4 noisy transmission vs Porsche magic grease absence

[928996]

Hi all, I'm not new to Porsche but new to Renntech. I bought my Carrera 4 in september. The p.o. specified that the transmission was a bit Noisy and I bought it like that cause I do all my mechanics myself (usually). The care was in excellent general condition. Cause we have looong winters here, I planned to take out the drivetrain for my winter project. So now that I'm in, I'll do some maintenance on the engine like changing the oïl separator, IMS bearing, RMS, and everything I can to have peace of mind.

My post is about the tranny. I'm aware of the Pinion bearing failures and everything I read about noisy transmission was followed by: The first check to make is to drain the oïl and stick your finger in the drain hole to see if there is the Porsche magic grease that came off the pinion bearings. That is the first thing I did when I drained and saw nothing like that. I just had a bit of black deposit just probably normal due to the age and mileage of the transmission. The car has 100k miles on it by the way. I opened the transmission and did'nt see any grey magic grease like I saw on other related posts or Youtube. The condition of internal parts of my transmission look excellent. I would like to know if my pinion bearings could be the problem of the noise I hear from the transmission even if I don't find the magic grease that should have come out from the bearings? Since I'm not on an open budget I would'nt change these bearings without beeing sure cause first it's very expensive and second it's a huge task.

I found a cool DIY about changing the bearings but it's for a C2. Mine beeing a C4 there is no hole at the end of the primary shaft where I need to put a special tool not to break it while I press out everything to the bearing. Is the shaft of a C4 also hollow ? Does anyone did that in a Carrera 4 transmission?

I called a specialist and told him what I wrote and he told me that it could be noise coming from the differential part of the tranny. He also told me that there was not much to do with that. I did'nt find anything on the net about other reasons than the bearings that make trannies noisy on these cars.

Could someone help me please?