so i bough a new driveshaft for my e36 from driveline specialist in portland.
Once installed, i had to leave the day after for our planed vacations, around 2000km trip in the Quebec province, so i didnt have time to realy try the car.

The driveshaft was not giving me satisfaction. There was shudder at 20-40mph and a steady humm at 60mph. I was realy shocked and frustrated.
So i went back to the service manual and did read all the section for the driveshaft again and again...once i figured out what was wrong. Generaly:

1-the driveshaft must be perfectly in line, centered and aligned
2-the transmission on that car is 10mm offset to the passenger (???)
3-center sliding coupling must be free of movement =>that was not on mine. There is a collar to squeeze a rubber so it wont vibrate. Torque spec is 89 in lb, NOT 89 FT LB !!!! which is 7.5 ft lb. So that means it can be just torqued by hand.

I cant belive the difference it makes. Gawd, its the same guibo and u-joint system that i have on my 02.
I believe the sliding relieve a lot of stress induced into the guibo when the engine or rear suspension subframe rock for/aft.
I can only imagine implementing that on a 02...

But, even if the car now runs as smooth as butter, there is still a noticeable humm at 60mph, and i know it comes from the new driveshaft, so i cannot still give credits to driveline specialist.
I will try to balance it myself with my vibration analyser...so, lesson in progess...dont miss read units, in/lb is not the same as ft/lb.
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1976 turbocharged 2002, 14psi, T3, 70%LSD, urethane bush, 36x15 intercooler, 63mm tby,SDS EM4F, 5sp overdrive. Bilsts. Tech edge wb02, datalogger, recaros.
1974 2002 auto
1992 325i
1991 318is
1985 XR4TI, 22psi
1986 Toyota pick-up
1997 Pathfinder