DIY - Transfer Case Service

[Clifton]

Originally Posted by Andy_Kay

how about wrapping it with some wire to hold it in shape - so it can stay in that candy cane shape. I think I'll give that a go and report back

You may be on to something. One thought I had was feeding a wire coat hanger into the plastic flexible tubing. Then form a candy cane shape before inserting into the fill hole. That would help to add and maintain the hook shape and would not impede the flow of oil during the extraction.

[Chilled]

Andy_Kay
I've got some pic inside the TC, hope this helps.

https://f15.bimmerpost.com/forums/sh...&postcount=161

You would have to find a way to snake the pipe back away from the fill plug towards the other side.

[scotty339]

Originally Posted by Clifton

You may be on to something. One thought I had was feeding a wire coat hanger into the plastic flexible tubing. Then form a candy cane shape before inserting into the fill hole. That would help to add and maintain the hook shape and would not impede the flow of oil during the extraction.

I used this pump with a 8 in piece of brake line, bent into a candy can shape. Insert the brake line into the end of the tube and it works perfectly.

Performance Tool W54173 200cc Extraction & Fill Pump

[M302_imola]

Ordered new cabin air filters, front and rear diff fluid w/ new drain/fill bolts, and Transfer case fluid from FCP Auto. It just arrived and I realized I'm an idiot and didn't order a new replacement drain/fill plug for the transfer case. Is it a huge deal to reuse the stock plug? I hate to postpone my service another week while I wait for the new plug, but will if necessary. What you guys think?

[Clifton]

Originally Posted by M302_imola

Is it a huge deal to reuse the stock plug? I hate to postpone my service another week while I wait for the new plug, but will if necessary. What you guys think?

I don’t think it will hurt. You *might* get some weep, but if you order the fill plug and then swap out later, I’m not sure I’d worry. The plug can be swapped pretty quickly if you have correct tool.

[Chilled]

Originally Posted by M302_imola

Ordered new cabin air filters, front and rear diff fluid w/ new drain/fill bolts, and Transfer case fluid from FCP Auto. It just arrived and I realized I'm an idiot and didn't order a new replacement drain/fill plug for the transfer case. Is it a huge deal to reuse the stock plug? I hate to postpone my service another week while I wait for the new plug, but will if necessary. What you guys think?

The diff and TC plugs are all identical. Put the new plug into the TC and re-use the fill plug on the rear diff. It easier to get to the rear diff fill plugs then the TC, imho.

BTW, don't forget. If you are dropping the reinforcement plate for the front diff. That plate needs new bolts.

[M302_imola]

Originally Posted by Chilled

The diff and TC plugs are all identical. Put the new plug into the TC and re-use the fill plug on the rear diff. It easier to get to the rear diff fill plugs then the TC, imho.

BTW, don't forget. If you are dropping the reinforcement plate for the front diff. That plate needs new bolts.

Good deal, I wasn't sure if they were the same. I've found a few drops of fluid towards the rear of the vehicle on the garage floor lately. Not sure if it's from the TC or rear diff. With that being said I'll prob use the 2 new plugs on the TC and rear diff and reused plug on the front diff. I won't be dropping the reinforcement plate. Appreciate the insight.

[Chilled]

The Front diff seems to be the hardest to get to and diagnose leaks. I would say put new plugs in that. If the TC is leaking that would be inline with the center of the front doors.

Please let me know how you manage to do the Front Diff without dropping the reinforcement place. All guides and people doing it, seem to have done it.

I am yet to attempt it as I haven't bothered to buy the bolts for it.

[M302_imola]

Originally Posted by Chilled

The Front diff seems to be the hardest to get to and diagnose leaks. I would say put new plugs in that. If the TC is leaking that would be inline with the center of the front doors.

Please let me know how you manage to do the Front Diff without dropping the reinforcement place. All guides and people doing it, seem to have done it.

I am yet to attempt it as I haven't bothered to buy the bolts for it.

I thought the TC was a bit more toward the rear of the car. So going off what you're saying it must be my rear diff that has the slight leak. I'll investigate more. I'm having a local shop do the front & rear diff and TC fluid change. I'll recalibrate the TC using ISTA software. You referenced the reinforcement plate and I misunderstood. My mind went to the subframe that's a tight squeeze between the TC. So you have to replace the bolts on the reinforcement plate? I def didn't purchase new ones

[Chilled]

The TC is directly behind the gearbox somewhere near the middle of the front doors. It can be done without loosening/removing the crossmember if you have short sockets/allen keys, or Tite-Reach extension(or the Strap-On version), or do some custom tooling and cut some sockets (me).

Tite-reach
https://tite-reach.com/products/3-8-...tension-wrench

My TC Post (just FYI, this thread has talks on oil types. Most do not correlate to a F15/F16)
https://f15.bimmerpost.com/forums/sh...2#post28214462


The front reinforcement plat is the silver plat that is under the engine sump. The thing you poke your hand through the get oil filter.

Has a nice view of it missing and the guy pointing at the front diff, in 5th pic
https://f15.bimmerpost.com/forums/sh....php?t=1874581

33306772888
https://www.realoem.com/bmw/enUS/sho...diagId=31_1173

[M302_imola]

Originally Posted by Chilled

The TC is directly behind the gearbox somewhere near the middle of the front doors. It can be done without loosening/removing the crossmember if you have short sockets/allen keys, or Tite-Reach extension(or the Strap-On version), or do some custom tooling and cut some sockets (me).

Tite-reach
https://tite-reach.com/products/3-8-...tension-wrench

My TC Post (just FYI, this thread has talks on oil types. Most do not correlate to a F15/F16)
https://f15.bimmerpost.com/forums/sh...2#post28214462


The front reinforcement plat is the silver plat that is under the engine sump. The thing you poke your hand through the get oil filter.

Has a nice view of it missing and the guy pointing at the front diff, in 5th pic
https://f15.bimmerpost.com/forums/sh....php?t=1874581

33306772888
https://www.realoem.com/bmw/enUS/sho...diagId=31_1173

So pertaining to the bold up above. Does the front diff have both a drain and fill plug in the f15? Not sure if it's any different in F85?

[Chilled]

Yep, your front diff will have a drain and a fill plug.

[JamesInSJ]

Originally Posted by JamesInSJ

As long as I can get this 14mm socket up in there, looks like this will work great.

Start with open end 14mm, hex is fully inserted with 1-2mm to spare. Break it loose. Then insert the 14mm hex through the 14mm ratcheting end (still 80-90% of the way in), and back the bolt out until you can just use your fingers to remove it.

Would like to report that this approach worked perfectly, using these tools that many of us already have. It was easy to navigate the socket + wrench into the space, and I used a small screwdriver pressed against the back of the socket to help get it in place. Once I put a little pressure on it, it held in place for me to give it a few whacks with the mallet to break it loose. Used fingers to remove it the rest of the way.

[M302_imola]

Originally Posted by Chilled

The Front diff seems to be the hardest to get to and diagnose leaks. I would say put new plugs in that. If the TC is leaking that would be inline with the center of the front doors.

Please let me know how you manage to do the Front Diff without dropping the reinforcement place. All guides and people doing it, seem to have done it.

I am yet to attempt it as I haven't bothered to buy the bolts for it.

FYI, FCP Euro just did a DIY on the front diff. Dropped the reinforcement plate and didn't appear to replaced the bolts.

[Chilled]

No idea. He did do them up as stretch bolts tho. Maybe just an oversight?

[M302_imola]

Originally Posted by Chilled

No idea. He did do them up as stretch bolts tho. Maybe just an oversight?

Could be, just bringing it to your attention since your post above.

[Tomcat_F15_STL]

Originally Posted by Chilled

No idea. He did do them up as stretch bolts tho. Maybe just an oversight?

Originally Posted by M302_imola

Could be, just bringing it to your attention since your post above.

I only do 45deg as a final rotation - works for me. Manual says replace them. There's no way I am gonna pop for new bolts every time that stiffener comes off the vehicle! Most of us do not print money.

[M302_imola]

Originally Posted by Tomcat_F15_STL

I only do 45deg as a final rotation - works for me. Manual says replace them. There's no way I am gonna pop for new bolts every time that stiffener comes off the vehicle! Most of us do not print money.

I thought a full 90 def after was a little much. Appreciate the reply.

[crystalworks]

Originally Posted by Tomcat_F15_STL

I only do 45deg as a final rotation - works for me. Manual says replace them. There's no way I am gonna pop for new bolts every time that stiffener comes off the vehicle! Most of us do not print money.

I do the same thing with the reinforcement plate bolts on my E53. Had it on and off at least 10 times now. Will take the same approach to the F15 when I do the front/rear diff fluids.

[jluzbet]

at 110K, never changed it would it be a bad idea?

[Chilled]

Originally Posted by jluzbet

at 110K, never changed it would it be a bad idea?

I would say that changing oil that late in something that has clutch packs could cause issues. There is probably a bit of clutch material in the oil now that allows it to actuate, and engage.

If you remove this material, you may find that it starts to struggle with engagement of the front wheels to the amount it needs.


Not saying you shouldn't do it, but just full disclosure and be aware. Yes not doing the change, would probably be a worse choice.

[crystalworks]

I'd change it. And have on other xdrive bimmers with higher mileage. Just my .02 though.