Transmission and transfer case fluid change/reset - BIG difference

[wpoll]

Originally Posted by Spartan

... So I considered the trans might or could do with a fluid change. A lot of people advise against changing it all in one go and suggest drain and top up each time over a period of months. But how do you do this if both are on the bottom?

I'm still (mostly) running the factory fluid, at 275,000kms and I'm way too scared to change it!

I have replaced the internal rubber seals on the valve body (bridge seal, jump seals and mechatronic seal) and used new ZF Lifeguard 6 fluid to replace what was lost doing this task - so maybe 2 litres of new fluid in the full transmission (~12 litres?).

The fluid can be drained (via the small drain port) with the engine off but do NOT open the larger fill plug with the engine off or the fluid at full temp.

The method to drain and fill the transmission AND set the fluid level is... messy.

(This is for a steel trans. pan - not plastic)

1. With the car raised and level, the transmission warmed and engine off, open drain bolt and drain fluid.

2. Remove pan and drain remainder of fluid from pan. Clean pan, magnets and replace trans. filter.

3. Using a new pan gasket, re-install pan.

4. When trans. is cold (> 5 hours) open fill port and pump new fluid into port until port overflows slightly (~4 litres). This requires a fluid pump and a small hose to get into trans., inserting the hose to get around fill port baffle (white object in this image): -





5. When fill port starts overflowing slightly, close it up (just hand tight) and start the engine. Run through all the gears with foot on brake(!) - pausing for a few seconds in each gear. Monitor trans fluid temp via scanner and once trans. fluid temp reaches 35deg.C. open fill port again and pump in additional fluid until port overflows once again. This can take another 1-2 litres and must be completed before trans. fluid temp. reaches 50Deg.C.

6. Once fluid overflow slows to a slow drip (and trans. fluid temp remains between 35 and 50Deg.C.) close fill port and torque correctly.

Sounds harder than it is but you DO need to car either on a hoist or up on four decent ramps. since you need the car to be very level AND up in the air so you can work underneath it with the engine running.

Not my favourite job but I've done it a few times now (checking the fluid level from time to time).