I would never touch the transmission fluid. It is not really recommended to change the tranny oil, unless something really wrong with it. Don't believe me, call lilltle car shop. They are highly recommended by the badger bimmers
. 414-263-2500 is their phone, call and ask.
As far as the differential goes, I always thought they were sealed units. I could be wrong though.
Here is info you needed.
Green label (1992) Gear Lubricant Special (GLS)
Red label (1992) DEXRON III Type ATF
No Label (1992) 80W GL-4
1993 or later DEXRON III Type ATF
1992 - 1996 DEXRON III Type ATF
1997 and later Special Lubricant Fluid (SLF)
1992 1.2 quarts
1993 & later
318, 320, and 325 1.2 quarts
328 & Z3 1.3quarts
Automatic Transmission 3.2 quarts
4 Cylinder Models 1.2 quarts
6 Cylinder Models 1.8 quarts
Final Drive Unit Hypoid gear oil
PS: quit it, its not that cold outside. I am the one near the damn lake. :P