Rear differential drain and refill

[aNoodle]

So I finally did it after 120,000 miles. I know I really should have done it earlier, but it seemed like it might be involved. Wow, what a joke. Pop the fill bolt, pop the drain bolt, let it drain, pump in the new stuff and close it up. Couldn't be more easy (well....it did take four stores in Atlanta to find a 14mm alan wrench/hex bit).

Two questions:

How often do you guys drain your differential fluid? (Does anyone really believe it's "life time"?)

What oil do you guys use? (I put in Mobil 1 Synthetic 75w90...should of only taken 0.95 liters but an extra 0.1 liters seems to get lost in the pump.)

 

[codex57]

http://www.bmw325i.net/maint_rear_diff_fluid.shtml

 

[aNoodle]

I love the BMWBoard, but knowledge of car maintenance is wholly lacking here.

 

[codex57]

My car's a year old. Haven't exactly had to worry about much maintenance yet.

 

[aNoodle]

My car's a year old. Haven't exactly had to worry about much maintenance yet.

Right on, I didn't mean to single you out. Acutally, thanks for the good link...I've used that guy's site a number of times. I'm just frustrated by the lack of tech talk on BMWBoard.

 

[jrt67ss350]

Well, there seems to be an overall lack of good tech talk in the E46 section.

As far as the differential fluid goes....
No fluid is "lifetime." It's a molecular impossibility, and even if it was, they wouldn't put drain plugs in the differential housing if it was really a "lifetime" fluid, now would they? I think it's supposed to be replaced at Inspection II anyways. Given how easy it is to change the fluid and the low cost of two quarts of good differential oil, I'd change it every few years as a good prevantitive maintenance.

I just changed mine last weekend. I used the same oil you did.