Anybody replacing diff and transfer case oil at less than 100k?
 

"Lifetime". What an awesome word.. for ze BMW bros.

Can't decide when to change the differential and transfer case (just another diff) fluid. BMW calls for 100k miles. I'm at '62k. Here I am having auto tranny problems.. so I'm also thinking about preventative maintenance on the diffs. But then again.. diffs are waaaay simpler than transmissions.

Anybody changing oil sooner than 100k? X is going in next week for auto fluid refill anyway. I don't want to spend the extra coin on the diffs unless you guys feel it is important at 62k.

Thanks a bunch.

Slightly off topic; Its amazing how many posts accumulated on this forum in just 24 little hours! 1.7 pages worth. No one can say this board has settled down! Good job keepin' it goin' guys!.
:thumbup:

I changed my front/rear differentials, transfer case, transmission (fluid/filter) at 48k. Running well thus far at 57k. Be prepare to buy some drain/fill plugs for the differentials depending on the type of plugs that came with your car. If you have the normal plugs with crush washer, then you can re-use them (get new washer if you like). If you have the newer plugs with built-in rubber seal rings, then the safe bet is to get new ones.

Had all of my various power transfer fluids changed at InspII, ~60k miles,by an excellent Indie in Asheville,NC:
front/rear diff, transaxle, manual trans.
Reasonable and worth it, imo, if one is keeping it for 100k or, more.
GL,mD

OK, so what's the latest best oil for use in the differentials, transfer case and in my case, manual transmission?

I'm leaning with the following, but also looking for any EXPERIENCED input if it's out there:

5 spd MT - BMW MTF-LT3 (BavAuto)
TC - Castrol or Lubro-Moly 75w90
Front and Rear Diff - Castrol or Lubro-Moly 75w90

- M54 Lover

I recently did both the front and rear diffs with Valvoline Syntec 75w-90. To my demise, the rear had a leak in the front input shaft seal. New fluid, flowing better - went right out in 2 days and I burned up my diff on the highway.

Just a note - make sure you're not leaking any fluids right now before you replace it or you could accelerate the damage.

Eventually, I had to get a used diff. My '06 has 90K on it but the used rear diff has 18K. The indy I got everything replaced at used the original Castrol XAF-XJ fluid. Check with the dealer and confirm with another as it may be different for the models with and without X-drive.

I use Redline 75w90 in my differentials, FWIW. I change it every 30k miles or so in my 5-series. Last change, the stuff coming out looked nearly as good as the stuff coming in... so I guess that tells me I"m using good oil, and, 30k is probably overkill.

MG

The indy where I got my diff replaced said they'd use either the original BMW stuff or Royal Purple, whichever they could get sooner.

everyone should stick to BMW OE fluid. Not sure why ppl feel that they NEED to "UPGRADE" some aftermarket brand. As if BMW used the worst fluid in the world or something. Just stick with factory fill and you should be safe.

I have never changed the fluid in diff or transfer case. Once around 180,000 or so I drain and refilled the transmission fluid. I currently have 241,000. Maybe lifetime really means life time. I have been think about changing the transmission fluid and filter because of all the talk we have had about fluids but I am not sure. Like waynesworld said he changed his fluid and the diff crap out 2 days latter. I really don't want that.

wally, that 241k miles on your X, may be the top mileage here on the board,
based upon my fading memory!
Congrats!
GL,mD