my decision to flush out the transfer case was based on what was in there when i drained it.
If you drain yours and get somewhere near the 2 cups of fluid that are supposed to be in there, then I would just refill it. But my oil was thick and gooey, with lots of metal particles. The amount of work is not really any different, just a little more time.

 

Thank you Bojangles for the excellent write-up.

I don't own a Jaguar, but I have a lady friend who owns a 2002 X-type, and in researching this issue with her car, I came across this thread. I wanted to share my experience with it in hopes it'll help someone.

Her car has been leaking out the right side of the transfer case for some time. She has 55K miles on the car now. She frequently smells burning oil from inside the car.

She had the dealer change the seal about a year ago. It kept right on leaking. The dealer told her that the internal seal between the transmission and transfer case must be leaking, causing the transfer case to overfill, and forcing oil past the right side axle seal. They told her the transfer case is a sealed unit, not serviceable, and her only option was a new one for over $3K installed.

On top of all that, her transmission has started lurching on her, just occassionally, and typically after making a turn and attempting to accelerate. It's like it slips for just a moment. From reading threads, this appears to be a leading indicator of an imminent transmission failure.

So anyway, after learning of all this and reading all the threads I could find, we decided to take a shot at fixing these things from the outside, figuring we had little to lose and it was worth a try.

I started with the transmission. We did 3 drain and refill cycles, each time removing and replacing about 3-1/2 quarts of ATF. I used Valvoline Mercon V synthetic (which they claim meets LT71141) and on each refill, we mixed in an appropriate amount of Lucas transmission anti-slip and seal conditioner.

The original ATF was very brown, clearly burnt and in need of changing. This notion that it's a lifetime fill is BS. Maybe if the lifetime is 30K miles I could buy that. After the 3 changes, it's pretty red, just a hint of brown. I figure the oil is about 80% changed.

She drove it of course between these changes. After the 2nd change, she has yet to notice that slip/lurch as she accelerates after a corner. Hmm. We are cautiously optimistic.

Anyway, we also changed the Transfer case oil, filling it through the drain plug per Bojangles excellent idea. On her car, there's no room to get a valve sandwiched up there, and I didn't really see the need for a valve anyway. In fact, the drain plug is pretty buried and there really wasn't any way to get a fitting off and a plug back into the hole without losing lots of oil, just because it was so hard to get to.

So I rigged up a few fittings just to get the plug into a more accessible location. Sorry, I didn't take a picture. But I used a 1/2" x 3/8" npt brass pipe bushing screwed into the transfer case, followed by a 90 degree 3/8" npt brass elbow. Fortunately I had a 3/8" magnetic pipe plug. This positioned the drain out and pointing down to where it was easy to get to. I used a 1/2" hose barb x 3/8" pipe fitting and ran a 1/2" clear vinyl hose up to the top of the engine, to a funnel.

When we drained the transfer case oil, we got a full 600ml out of it, and it looked exactly like what we had pulled out of the transmission. So perhaps the dealer was right, oil was moving from the transmission to the transfer case and causing it to come out the seal on the right side axle.

Anyway, we refilled it with 75W-140 synthetic gear oil, and we mixed in some seal conditioner with it as well. We poured 600ml down the hose figuring we'd lose 50ml or so when we went to put the plug back in, plus what was caught in the hose.

On top of all this, I also spent a fair bit of time insulating the pipe from the transfer case. I wrapped the pipe with fiberglass exhaust wrap and then put some foil backed fiberglass exhaust insulation around that.

She drove it for awhile. She got the smoke smell really bad, but I figured there might be a couple reasons for that. First off, there was coked oil covering the exhaust pipe in that area, and I put the insulation over it, so it was bound to be getting hotter and burning that old coked oil some more. Second, I've used this wrap before, and it's not unusual at all for the wrap itself to smoke for the first few heat cycles you put it through.

Anyway, a few days later, with the smell diminishing somewhat, we jacked it up and crawled under it again. To my surprise, the underside of the transfer case was dry. Every time I had seen it before, it was wet with oil that had run out of the right side seal. Hmm. We drained the transfer case oil. It looked exactly like what we had put in there, and we got out just under 600ml. We put new oil back in it, again with seal conditioner.

After a few more days of driving, the oil burning smell has stopped.

The bottom line is that after doing all these things, the transfer case appears to not be leaking anymore. To what extent I can credit the seal conditioner in the ATF, the seal conditioner in the transfer case gear oil, or the pipe insulation, I'm not sure. All I know is that for the time being at least, the leak appears to have stopped and there doesn't appear to be any ATF getting into the transfer case. On top of that, the transmission hasn't done it's slipping/lurching thing.

I wasn't overly optimistic going into this job that we'd be able to effect much, if any, of an improvement. I figured it was worth a shot, though, considering a new transmission and transfer case would cost her probably $7K or more. So far, it seems to have worked. I still can't believe it's any kind of a permanent fix. But hey, if it gets her 6 more months, or a year, or whatever more life out of her transmission and transfer case, it was well worth the hundred bucks and few hours we spent doing it. Your mileage may vary of course.

 

Wow.. good friend you are man... I hope you get the "benefits" for all that work :P

 

Technically you're right, Valvoline generally reccomends MaxLife ATF for LT71141 applications like the Jatco. But I came across this document from Valvoline that says Mercon V is suitable as well:

http://www.e38.org/Mercon%20V%20ATF%20Letter.pdf

(they have a similar letter for MaxLife)

MaxLife already has the anti-slip and seal conditioner additives. But I wanted a synthetic, I think it's particularly important in ATF which sees a lot of heat. So I went with Valvoline Mercon V because it's synthetic and used the Lucas additive because I had heard good things about it.

Here's a full app chart showing Valvoline's reccomendations:

http://www.bimmerfest.com/forums/attachment.php?attachmentid=138868&d=120534771 5

 

Thanks for the idea of filling from the drain plug, worked great and beat the hades out of taking half the car apart to access the fill plug!