Took my '00 Disco II across country from Colorado to Kentucky and back. Truck did great, no issues whatsoever, but I noticed my leak in the transfer case has steadily gotten worse to where it's a visible constant drip after the vehicle has been driven awhile. I can also smell the hot gear oil after a long drive. Truck has about 130k miles now.

What needs replacing here? Is there some seal or gasket that is notorious for going bad? Is this common and is there a write-up for the repair? I can't really get a good look as to where on the unit it's leaking, it drips from the lowest point and the whole case has fluid and grime on it (from the front diff leaking and fluid blowing back onto the trans case)-- so it's tough to tell the origin.

I also have to do the front & rear diff seals as they are leaking too-- very slowly, however, I only have to top the fluid off every 3-4 months, if that. Can someone give me a link to the best place to buy the diff seals or any parts I need to seal up the transfer case?

Had a ton of fun on the drive out there, it was great to see how much oomph this motor has at sea level -- HUGE difference, the torque this thing puts out below 3k RPM is pretty incredible. I average about 16.5 mpg at home, but was getting about 15 mpg the whole trip. The thin air up here must improve gas mileage some, or maybe I was enjoying the extra power too much.

 

Mine leaked when I traveled highway speeds pulling a motorcycle travel all day. It had never leaked before. Once at home, I drained and refilled and added White Sheppard/Blue Devil Stop Leak. Hasn't leaked since however I have not been on the highway not stop for hours and hours.

 

Look at the inspection plate, that is a common area for leaks. If you smell burning, check the front output seal (where front drive shaft meets transfer case). When mine started leaking there it was dripping into the exhaust and burning off.

 

There are a few places that leak oil. Front and rear output shaft seal, 10 bolt inspection plate and the input shaft seal but for that one you need to drop the transfer box away from the autobox. More time consuming than difficult. If replacing seals the OEM is Corteco which seem very good particularly if they last 11+ years and 120K+ miles like mine did.

 

I also just noticed a leak possibly from the transfer case but Im not certain yet as it could be engine oil. The cross member directly below my t/c has several drips on it.

 

There are 2 things you can try before pulling the t-case and replacing seals.

1. White sheppard stop leak. It's good stuff my t-case doesn't leak anymore.

2. You can reseal the 10 bolt face plate. I bought the make your own gasket material from autozone and cut it to fit.

Other than that it's one of the seals. First thing you need to do is buy some degreaser and get it cleaned up so you can try to track the leak.

 

Just went through this with my 03. It was the inspection plate leaking on my t-case and possibly the rear output. Save some trouble, and make a gasket for the inspection plate. I tried twice to get it to seal without, then gave up made a gasket and it's fine. I refilled with Mobil1 85-140 and a bottle of white shepherd. Been dry so far.
Hope that helps.

 

I drained my leaky transfer case on my ex 2001 D2.
I put in synthetic 90W and it stopped leaking!
The synthetic must have expanded the seals?

 

white Sheppard gets my vote. it stopped the leak that I had.

 

it helps if you don't fill the transfer case to the top