When I first got my 325, it was almost impossible shift into first or second gear when cold, and quite easy to miss shifts (beat the balk rings and go "crunch"). I'd always read in the BMW CCA Roundel about how good Redline MTL (Manual Transmission Lubricant) was, so I'd figured I'd give it a try. It's a synthetic-based lubricant, with friction modifiers specifically designed to work with manual transmission synchronizers. Most lubricants sold as "gear lube" are too slippery to let the sychros do their job properly (remember, synchros use friction to bring gears up to matching speeds), and as well, non-synthetic oils get very thick when cold, which can make shifting very difficult in the closely-toleranced BMW gearbox.
Well, I put in the Redline MTL, and what a difference! The car is a dream to shift, even when stone cold. It's silky smooth, and never misses a shift. It really does feel like a new transmission. Well worth the rather steep cost ($18 a quart!). I strongly recommend this stuff to anyone with a manual tranny, especially if you find it hard to shift when cold.
You can get Redline at one of the contacts below, and then get your local Mr. Lube to put it in for you (they charge $15 for this service, but it sure beats mucking around under the car with tranny lube pouring down your arm). Most BMWs take about 1 1/2 quarts for the tranny, but check your book before buying.
Below is the web-site for Redline oils, you can read about their MTL, and the rest of their line of racing lubricants. (Note that this takes you out of the Hill House, using a new browser window. Close the new window to return here):
If you live in the Lower Mainland, you can buy Redline products off-the-shelf at Mopac, at the address below:
MOPAC AUTO SUPPLY LTD
3488 Kingsway
(3 blocks west of Boundary)
Telephone 435-4233
Happy shifting!!