Invaluable information in this thread. Thanks!

X5 e53 3.0, Ratchet clacking sound under hard acceleration, quiet on slow starts
 

This is a great thread! I've got a 2003 X5 e53 3.0, with 150,000 miles that made a ratchet clacking sound under hard acceleration, but it was quiet on slow starts, so basically exactly what everyone on this thread said theirs did.

Here are some tips I wished I knew before doing this transfer case chain job, kinda following my nose and most of the instructions from everyone else. Passing 'em forward:

1. I rolled the front wheels up on 7"-8" high car ramps and leveled the rear end, wheels off the ground, on jack stands. That was enough, with trans in neutral and e-brake off it was easy to spin rear wheels for spline/flange alignment.

2. I removed the TC completely, which clearly made it easier to work on and clean internally than it would be if you left the back half attached to the transmission and did it all lying on your back. Yes this job can be done without completely removing the TC because the two gears for the chain slide out. The circlip that holds the front drive shaft gear on was a b#tch, so I left that one it place, put the new chain for a NV125 New Process TC (from Cobra Transmission parts, check your TC model number, on badge, easy to see) over both gears and gently tapped the main shaft gear in place, no problem.

You DEFINITELY need a star ratchet wrench, e10-e12 mm combo (see pic, mine was a Powerbuilt brand, eBay, $9.00 worked very nice) and separating the TC from the trans is no prob.

3. You DO NOT need to unbolt the drive shaft ends, front or rear, at the far differential pumpkin ends!! Just remove the 6 rear drive shaft bolts (and the rubber damper disc) right close to the TC. Knowing this woulda saved me a bunch of time and hastle.

On the REAR drive shaft, just remove the center support and have someone pull shaft (with hands) away from the TC and it'll just slide off it's center pin. The front drive shaft is splined so it slides right out of TC when you separate it from the tranny.

4. You DO NOT need to remove the exhaust, just unbolt and tweak the alum heat shield to get to the crossmember bolts. BE CAREFUL! Twice I dropped the cross member bolt or socket INTO the hollow cross member :stickpoke, necessitating removing the crossmember to tip it out. Of COURSE I was always on the LAST bolt both times it happened...

5. You DO NOT need to remove the large 36 mm nut that secures the drive shaft flange to the TC output shaft (unless you're replacing seals, bearings behind it). Leave it alone.

6. I used AC Delco Engine Sealant 88864346 to seal the TC case gasket-less halves. It behaves much differently than silicone, tougher, more firm, bonds to metal surface way better. Use it for EVERYTHING that needs sealing.

Since my seals weren't leaking I left them and the bearings alone. Don't forget to put a little bead of grease between the lips of the rubber seal before sliding it back on the trans output shaft.

The job overall was not too difficult, straightforward, and a tremendous savings ($100 DIY vs $2,000+ at the dealer). Thanks XPosters, you saved me again :thumbup:!

I just got done doing ths repair and did it your way leaving it on the car. It was surprisingly easy. I only removed the support frame, disconnected the driveshaft and bungee corded it to the exhaust to get it out of the way and then opened up the case and replaced the chain by sliding out the gears. The only thing I would add is that the gear with the snap ring has a dust shield on the outside that needs to be pried back so the gear pops right out when the snap ring is expanded. Leaving the transfer case on the car I was able to complete this DIY in about 4 hours going slowly and learning as I went.

I just finished reading all 16 pages of this thread. Nothing short of outstanding contributions.

BIG props to the OP for getting this thread rolling 7 years ago!

I'm not experiencing any of the chain slop symptoms on my 96K mile 4.4i but will have this great guide if I need it.

Thanks again folks.

Mike

I purchased my X5 with bad driveshaft/transfer case splines, so this was the first thing I ever did to it.

You are correct, it's not that bad of a job, if you have a lift, trans jack and air tools. I had the transfer case on the ground in about 45 minutes.

The chain and seals are pretty cheap to get (remember, this is a NV transfer case, not something BMW cooked up), but I ended up having two issues:

1) I couldn't find a replacement front output shaft (front shaft that has the splines for the driveshaft that goes to the front differential), and I didn't trust just doing the driveshaft spline extension. I had it torn down, new chain and seals, but just didn't like the looks of that front output shaft, so I bought another transfer case to start with, and also did the spline extension on the driveshaft.

2) Noting again that this is an NV transfer case, I'm not sure why they suggest using ATF in them, other than to cut down on noise when they're cold. Every other NV transfer case I've ever seen uses gear fluid, and the places I see rebuilding these units insist on use of gear fluid, or they will not honor the warranty. I'm thinking this is partially why these chains stretch so much more commonly than other NV units (or else BMW just under-spec'd these units when they incorporated them).

Disclaimer to above: All information is concerning the non-X-Drive units. I have not worked on the X-Drive ones.

Brump.
Gosh. I feel like the j3rk bumping on a 9 year old thread. Almost 10 yrs if one is counting


For those that have done the job, did anyone replace the `magnet' for debris or did you just wipe it clean.

I've tinkering with stuff I'm R&R out of the TC - just short of the chain, and plastic bearing+washer. The magnet is in my cart.

Nevermind. The lightbulb ran off in my head. It's it's analogous to the magnetism of a fridge gasket, I might as well just replace the dang thing.

I think I read almost every response on this thread. I don't recall seeing a note on anybody replace this part in the t-case while it was cracked open

I put in magnetic fill and drain plug about 6 years ago. Did the fluid change few weeks ago, and there was some fine particles on both. A lot more on the drain, but confirms they work. I don’t think anything will happen if you just wash your magnet.

Excellent Slick.
Did not even consider it

it's there but not exactly in front of me there
found it

https://cobratransmission.com/X3-ATC...467-Drain-Plug

Penny Wise, LB Foolish.

I'll wait till Cobra opens up so I can have a live conversation.
OE seals or their aftermarket seals at 75% LESS.....