Diffs and Trans case flush/fill

[BobsX53.0i]

2003 3.0i with 70K. First time flush and fill for the diffs. Drained fluid looked good as new. Hardly even discolored..used Mobil 1 75w90 for the refill.
The transfer case was another story....fluid was black and very thin. Refilled with Amsoil ATF. Basically the diffs really didn't need the flush, but I'm sure glad I did the transfer case. I would definitely recommend a flush/fill at 30K for the trans case from what I saw...and especially since it's a 5 minute job and only takes 1/2 qt. of ATF.

..bob

[AudiBMWSX45]

Good info. Is there a write up somewhere on how to do this?

[BobsX53.0i]

The rear diff and transfer case are very easy,..you can practically do these laying under the car without a lift. There's an obvious drain and fill plug for each. Both plugs are the same size and thread.
The front diff will require lifting the vehicle on jack stands,..removing the front wheels,..then remove the aluminum reinforcing plate under the engine ( 6 bolts). Then you'll be able to easily access the diff. Again, like the rear, the drain and fill plugs will be obvious. The rear diff takes a little more than a quart, the front a little less, and the transfer case takes 1/2 qt.(-- Fill to the level of the fill plug until it starts to run out--Mobil 1 gear oil for the diffs, ATF Dexron III for the trans case ).

Also, get an inexpensive hand pump for pumping the oil.
Torque---Diff plugs 50ft./lbs, Trans case plugs 35 ft./lbs

[lo_jack]

You might be surpirsed how many people forget these cars have a transfer case and that it needs fluid.

You might want to mention the size of the giant hex head that it takes to get the drain plugs out. I forget the size, but its abnormally large. My transfer case fluid smelled absolutely dank when I changed it. I went Royal Purple though.

[RDAvena]

Originally Posted by lo_jack

You might want to mention the size of the giant hex head that it takes to get the drain plugs out.

17mm hex.