My output seals arrived finally so yesterday I reassembled the transfer case.
First up was to clean the old gasket maker from the mating surfaces with Permatex remover. I let it soak for 30 min or so and whatever it was that was used to seal the case came off easily and then I cleaned it up with some 800 grit wet-dry sand paper.
The seals are just like any BMW axle, diff or other seal, and tap in relatively easily. After that I assembled the parts in the case, finally dropping the planetary gear and shaft into the transmission input gearing and shaft. I was a bit worried that the seals weren’t in far enough, or were in too far (no shoulder for them to seat on in the case), so I filled the bottom of the case with a little Dextron III and let it sit for a while while I put the gasket maker on.
I opted for Permatex Optimum Max Flex black RTV as it is suitable for automatic transmissions, and the non x-drive transfer cases gets filled with Dextron III. Frankly the stuff was a pain, but hopefully it made a good seal. It’s very thick and tough to both squeeze out of the tube and to get a steady, precise line that adheres to the case. Therefore I had to make a bigger hole in the applicator and ended up with a bigger line of sealant.
The bolts went in until the stuff just squeezes out, then it sets for 60 min. After which I torqued all the bolts to about 25 ftlbs, which is the standard, or there about for M10 bolts. Somehow I missed the fact that two of the case bolts were missing when I took this eBay case apart, so I used 2 random M10 bolts with washers. They were a little shorter so I used some blue loctite on them. I may rob two bolts off the case that is in the car when I drop it. Lastly I tapped the front output shaft dust cover on.
The latest thing to do before I install the case is to find a huge bushing receiver cup for the transmission mount bushing. I can’t get mine to seat the final 1/4” via the pound on it method. I have a very large ball joint press, but need a huge cup to use with it. Hopefully I can find something on Amazon, or make something.
I need a few days free to get this installed on the lift. It’s a big job and since the stiffener plate needs to come off I’ll also check my crank sensor shimming, replace the right tie rod (did the left a few months ago) and replace the lower control arms.