Which differential OIL to use?
 

Red Line? If so, what model/viscosity?

I have 1995 318ti

75W90

LS?

Redline 75W90

Our most popular gear oil, 75W90 is the preferred product in nearly all car and light truck differentials, both conventional and limited-slip, as it contains friction modifier which is recommended for limited-slip units. Our 75W90 Gear Oil is common in racing differential applications and can be used in transmissions and transaxles; however, other Red Line lubricants have better frictional properties for rapid synchronization. Exceeds API GL-5.

Used in the Club Sport.

how many quarts do I need?

Also, do you guys use a pump? or what do you use to let new oil in?

Site's down, but I pretty much followed this guy's instructions:

Ron Stygar

The only difference is I use a suction gun to drain what's just sitting in the bottom.

I should also mention that Redline hypoid gear oil smells like rotten eggs. Do not do this on a hot day, and wear rubber/nitrile gloves.

All hypoid oil smells like that, its the HIGH sulphur and nickel content that give it the gear box aroma... :)


Dave

buy 2 qts. you need 1.25/1.32 for the small diff IIRC.

My 1995 318ti has the limited slip option - "S209A Differential lock 25%" - per the VIN lookup. Also did the rear wheel spin test and both wheels turn in the same direction. Bentley manual states that cars with LS use 75W-140 gear oil, but most forums and tutorials are saying 75W-90 since this LS doesn't have clutch packs. Any advice?

I put Amsoil 75w-140 in mine year's ago and it's been fine.

Thank you, Bradestar.

Got the bolts off, which was surprisingly easy, but then noticed that both bolts that came out were different that OEM ones ones that I got on Pelican. Attached are a couple of photos of a new bolt compared to one that came out. New one has the o-ring and is shorter. Any thoughts?

Did some more research, and I think the bolts with the o-rings are a newer BMW design that superseded the bolts that use a crush washer. Ron Stygar's tutorial shows the same bolts that came off my car.

Even though realOEM shows the bolts using an o-ring also have a crush washer, I don't think that would make sense. Newer BMWs whose differentials/final drive plugs have an o-ring bolt don't use washers. Also, the torque spec for o-ring bolts is less than ones that use washers (44 vs 52 ft-lb).

Anyway, I'm just going to use the old bolts with new washers. The only reason I got new bolts is because I thought the old ones would have o-rings and needed replacing.

Thanks for listening! Maybe this will help others who come across the same dilemma :)