Diff fluid changes and transfer case

[Jeff SJ]

I subscribe to the theory that tranny changes should be done prior to recommended BMW intervals whatever they actually are and I have done that. What about diffs and transfer case? I assume there are two diffs and a transfer case but maybe the transfer case is part of the tranny? I had the auto tranny service done and didn't ask that question. I searched but could not find technical info on doing these changes.

Info on doing this on this site?

Jeff

[JCL]

Differentials are pretty straightforward. 60,000 miles is a pretty good interval.

As you have an x-drive model, the transfer case uses a special BMW fluid. When it is changed, there is a reset procedure for the transfer case control unit. A service computer is required to do that reset. 60,000 miles is a pretty good interval for this compartment as well.

Yes, there are lots of threads here about changing these fluids. A search will show them. Search on the full site, not just the E70 forum.

[Jeff SJ]

I assume diffs have a fill and drain plug or will they require removal of the case seal and resealing. Sounds like I have to have the dealer do the transfer case(if they will). Or I guess suck the diff fluid out of the fill plug?

Jeff

[JCL]

Differentials (and the transfer case) have both a drain and a fill. If you are doing them yourself, loosen the fill before draining.

The differentials use 75w-90 (from memory - check yourself). They are not limited slip differentials, and thus don't need LSD additives or special oil.

The dealer will do your transfer case fluid change, it is a straightforward job.

None of these compartments have the risks that are associated with transmission fluid changes, they are simple drain and fill procedures.

How many miles do you have on it? Seems early for a change.

[Jeff SJ]

Originally Posted by JCL

Differentials (and the transfer case) have both a drain and a fill. If you are doing them yourself, loosen the fill before draining.

The differentials use 75w-90 (from memory - check yourself). They are not limited slip differentials, and thus don't need LSD additives or special oil.

The dealer will do your transfer case fluid change, it is a straightforward job.

None of these compartments have the risks that are associated with transmission fluid changes, they are simple drain and fill procedures.

How many miles do you have on it? Seems early for a change.

55k. Lots of 1300 mile round trips to park city ut at 80 plus. I figure it is close to time.

Jeff

[Xtony]

Originally Posted by Jeff SJ

I assume diffs have a fill and drain plug or will they require removal of the case seal and resealing. Sounds like I have to have the dealer do the transfer case(if they will). Or I guess suck the diff fluid out of the fill plug?

Jeff

Funny you mention this. I was recently reading somewhere that some new BMW doesn't have either a differential or transmission drain plug anymore. I don't think that's the case with the X5.

[ard]

I'd not do it without first seeing the BMW TIS for it.

But here are some pics:

RealOEM.com * BMW E70 X5 4.8i Transfer case, single parts ATC 700

Number 9?

and

RealOEM.com * BMW E70 X5 4.8i Final drive (front axle), parts, 4-wheel

Number 12.


I do get a kick out of the lablel, #15. Back in the day, a BMW could be expected to provide 200,000 miles of service. I want a BMW driveline engineer to look me in the eye and say "Yes, that fluid will last 250,000 miles and 20 years"

A

[JCL]

Originally Posted by ard

I do get a kick out of the lablel, #15. Back in the day, a BMW could be expected to provide 200,000 miles of service. I want a BMW driveline engineer to look me in the eye and say "Yes, that fluid will last 250,000 miles and 20 years"

A

It is even more of a stretch to think he would look you in the eye and say "Yes, we will maintain all computerized service tooling and still be doing flash upgrades and providing new control modules 20 years after the date of production"

You really expect to own one of these 20 years in?

I don't disagree with you on the benefits of changing the differential oil prior to 20 years, but I just wonder how relevent it will be.

[Penguin]

Originally Posted by JCL

I don't disagree with you on the benefits of changing the differential oil prior to 20 years, but I just wonder how relevent it will be.

I just got rid of my 1992 Ford Explorer with 198,000 miles last week, and a guy down the road has a 1991 Ford Explorer with 236,000 miles that he still uses... I gave him all my service manuals. So some people keep 'em running that long.

But I agree that today's BMW's are unlikely to be financially viable to keep running nearly as long as today's GM, Ford, or Toyota products. BMW's part prices, lower reliability, and inherient design which requires more proprietary tools and computer programming simply make it too expensive to keep them running after things start to fail. I think people are figuring this out, and that BMW's historic good resale is beginning to suffer as a result, e.g., 7 series resale.

[ard]

Originally Posted by JCL

It is even more of a stretch to think he would look you in the eye and say "Yes, we will maintain all computerized service tooling and still be doing flash upgrades and providing new control modules 20 years after the date of production"

You really expect to own one of these 20 years in?

I don't disagree with you on the benefits of changing the differential oil prior to 20 years, but I just wonder how relevent it will be.

I had a 1990 Q45 with 245k when I sold it.

Computerized. ECU, ABS, bus-linked modules, all the bells and whistles that the BMW has (no nav)... I still see it around, it is still on the road- now 20 years later.

I have a 2001 MDX. Computer. All the above plus more. 207lk, kids beater- but every single module works.

I have every expectation these car will indeed last. I do not expect software updates, but why would you want/need any??? After 5-10 years the software is stable, no need for new code. If you lose a module, head to ebay or a junk yard for a replacement. Indeed, given the numbers of units made, I really don't expect cars being junked due to 'lack of electronic gizmos'

For the last 20 years people have been bemoaning the advent of "these newfangled computer based control systems will mean the end of [DIYers, lifetimes over 10 years, etc]" and it just hasn't happened.

Now, what really happens is (a) people tire of getting screwed over by dealerships and would rather have a monthly payment, (b) most people have no clue how to use a screwdriver, (c) consumers use failures as an excuse to buy new- they don't want to be seen in 'old cars'

Dunno if I'll be owing and driving the X in 10 years when it hits 200,000 miles- but I am figuring I will 'pay it forward' for them with my maintenance. SOMEBODY will benefit from it.