Alexandroff

Hi again and greetings from Bulgaria.
Last night i finally got some time to change the transfer case fluid on my A8 D3 4.2 BFM equipped with a 6HP26A tranny. As i already got the right fluid, namely G 055 145 A2, i tried to find the filling plug without anny success. However one of the many bolts i saw was suspected to play the role of the filling plug. Unfortunately it is situated near the top of the transfer case, on its right side which makes it impossible to be reached without removing the exhaust pipes and transmission mounts.
So my question - does any of you have pics ot the plug and how am i supposed to reach it. thanks in advance!

jlbell

Whenever I asked my mechanic about refreshing the fluid he said: 1: it doesn't need to be serviced and to not be concerned with it. 2: whenever a customer insisted on it to be done the exhaust had to be removed/loosed and transmission mounts had to be removed. So from what I understand, you would need a transmission jack to support the transmission after the mounts are removed, then slightly lower it as to give access to the transfer case. Finally why are you servicing the transfer case whenever it isn't (by Audi's standard) meant to be serviced?

mishar

There is no drain plug. Only plug goes from the bottom and it is hidden by that wide aluminum mount. There is a hole for Alan key but it is not at the right place so it is very difficult to put the plug back. Anyways, that is not drain plug and you can't drain oil at all. You may add some of this.

MP4.2+6.0

See my reply 6 here with the picture of the center diff and drain plug: https://www.audiworld.com/forums/a8-...rance-2861255/

As Misha said though, there is no practical way to drain it on a 4.2. It can be done on a W12 or S8 if they have the auxiliary gear oil cooler that you drop to do the draining of both the front and center diffs, but that's a different set up than the std. 4.2 version of the tranny.

You still want to check it for fill, especially if there is any sign of a rear seal problem. Doesn't seem to come up with the 6 speed AT's as much, but did with both my prior 4 and 5 speeds, each with a similar Torsen set up back there.

Panelhead

I have worked on mine twice to flush and fill. First time I was only able to extract a little fluid. Like an 1/2 oz or so. But it took 4 oz and some brown thick stuff drained out with the new oil.
Second time I notched a "V" into the aluminum tranny support to allow better access. Got a couple ounces out with the trusty Mityvac. Did not take much to refill and the overflow was all clean.
I think the first time I was spraying fluid up higher into case. The thick stuff may have been on the walls.
The plug is on the driver side, blocked by the aluminum tranny mount. It is vertical orientation. Think is is a 8mm hex.
I made a gizmo from thin copper tubing to insert into to extract fluid. It has to be "U" shaped.
If I did top mine off I am happy. If a couple ozs of old was vacuumed out and replaced with fresh even better.

Alexandroff

hi again! ANY pic of the plug would be appreciated as i`m going to give it a try tomorrow... the one i thought to be the fill plug turned out to be the breather...

raj99

I did this a while back on my A6 (4.2) and understand the tranny may be slightly different the concept and approach for changing the fluid for the diff and transfer case is the same:
https://www.audiworld.com/forums/a6-...-oils-2843310/

Hopefully that'll help you.

Mister Bally

Another classic example of why purchasing a service manual is critical if you want to perform repairs on an Audi D3 (A8/S8).

mishar

As I said, there is no drain plug.

MP4.2+6.0

Hi again--

How about reading my last reply to you and the links w/ picture there?