Transfer case leak

[X5only]

I've been noticing a few drops of oil on the floor towards the rear of the car for the last one year. I'd assumed it's the trans since I could see a leak around the gear shift arm on the trans. At times I'd get a very harsh shift when the car is cold, and I bought trans service kit (solenoids, seals on the mechatronic, and trans oil pan and filter) but haven't had a chance to work on it. But today while doing engine oil change, noticed the leak is actually coming from the transfer case. The drain and fill plugs are dry and the leak seem to be coming from the points as depicted in the RealOEM diagram. There're seals in those connection points. Has anyone done this repair?

[andrewwynn]

Not in that transfer case but i rebuilt one on Chevy avalanche recently and it wasn't difficult to remove and replace the bearing and seals.

[Henn28]

That rear output shaft seal is a bad seal to leak I think.

I assume the x-drive rear output flange is like the non x-drive TCase flange…held on with a big nut. If so, I did a full rebuild on an eBay TCase last year and swapped it into my e53. I did the chain and all the bearings and seals (and front output shaft), except for that rear output shaft seal and bearing. Fortunately that bearing was fine. I was concerned that I wouldn’t have a way to re-torque the big nut holding that output shaft flange on. Or even hold it while it is being re-torqued.

I bet you could zip it off with an impact pretty easily, but the ring gear may need to be removed as it drives the output shaft. I wasn’t sure what was involved in getting that out. Would it just all come apart when the nut was removed…hopefully. On the other hand, if you can get the output flange (5) and dust shield off, you may be able to get the seal out by drilling a hole in it to pry on. Then you can drive a new one in with a deep well socket.



The other seals and bearings on the non x-drive TCase were easy though. You may want to consider the route I took. Get an eBay t-case and rebuild that one, then swap it in. With any luck that seal and bearing will be ok, and you can take your time on the chain, etc.

[EODguy]

Originally Posted by X5only

I've been noticing a few drops of oil on the floor towards the rear of the car for the last one year. I'd assumed it's the trans since I could see a leak around the gear shift arm on the trans. At times I'd get a very harsh shift when the car is cold, and I bought trans service kit (solenoids, seals on the mechatronic, and trans oil pan and filter) but haven't had a chance to work on it. But today while doing engine oil change, noticed the leak is actually coming from the transfer case. The drain and fill plugs are dry and the leak seem to be coming from the points as depicted in the RealOEM diagram. There're seals in those connection points. Has anyone done this repair?

I did and it wasn't too bad (or fun either) but I had a small crack in the seal that would only leak at certain shaft positions so if your shaft doesn't have any oil stains it's probably the same as mine bit still early on.

Replacement in-situ is doable but plan on making a 4"x4" post cut down and center drilled to make life easier on yourself....

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[80stech]

There should be a vent so maybe check that. The transfer case doesn't hold much oil so you need to get on any leaks ASAP.

[X5only]

Found code VTG "55C4 - No Message from DSC." There're no warning lights on the dash. Drained oil, there was plenty - it was dripping when I opened the fill plug but very dirty. Refilled with fresh DTF1 from the dealer ($45). Successfully performed Transfer Case Service procedure for oil change using ISTA software.

Will report back if the jerking and code disappear.