The 4 transfer case bearings and new front output shaft arrived from Cobra last week so today I test fitted it all, while I wait for the two output shaft seals which I bought from getbmwparts.com (along with 4 extra torx bolts to attach the TCase to the transmission as is suspect a few will be in bad shape).
After freezing the output shaft for a couple hours its two bearings went on with a little rubber mallet persuasion. The new shaft has a “key” milled into the splines which the old one doesn’t have and got me worried that it was somehow an incorrect part. Fortunately I had hung onto my old driveshaft splines as a paper weight and they fit like a glove.
Not sure why the new splines have a key slot milled into them, but these pics clearly show how badly the old shafts wear over time.
The bearings were a different brand (old ones were FAG, new ones are a Japanese brand) but fortunately they are all stamped with the part numbers, making the replacements easy. Below is the bearing that supports the transmission input gears, into which goes the planetary gear set.
The magnet pops back into its little spot:
Finally the new chain goes onto the input gear first, then onto the output shaft gear, before the gear is pushed into place. There is just enough slack to make this happen. Photo below shows the amount of slack in the new chain after assembly.
The only bearings I didn’t replace were the needle bearings inside of the input shaft gears, and the main bearing supporting the rear output shaft and ring gear. I’m not sure how the needle bearings come out, nor were they offered by cobra, and the rear output bearing would require removal of a huge nut to get the flange off so the ring gear can slip out, giving access to the bearing.
Still to do is to clean all the old, baked on gasket material without gouging the aluminum, clean the cases really well, pop the seals in when they come, and reassemble the thing for good. Not looking forward to the swap out, but I’ll do some other long awaited maintenance too while I’m under the car, with the stiffener plate off.