BMW X5 E53 - 3.0D Auto Transmission issues

[bmw328]

Good morning to all,

Recently bought a fairly clean (considering the age) 2002 BMW X5 3.0D Auto marked as non runner, "Not getting gears, forward or back".
It had the GM transmission...
When checking out the car, I checked the gears and it all of a sudden had forward and reverse gears (Stunned the seller).
Ended up driving car +-100Km with some slippage on full throttle in higher 5th gear before it lost gears again and it had to be towed the final 20km.
What I have done:
X Drained about 5L transmission fluid, changed filter and added +-8L fresh fluid back.
X When engine is running, unplugging "transmission electronics" to basically rule out electrical failure by transmission only running in hydraulic mechanical mode. (reverse and one gear forward)

Strange thing is. When transmission is COLD, it does select gears, but once it heats up (Example 5-10 min driving, it looses everything.) I have even tested this theory while its idling. (At first forward gears & reverse, 5min later nothing)

Any advice, comment would be appreciated. Failed clutches or torque converter?

 

[Gordvisr]

Not a guru on transmission side but here goes , did you top up with correct oil for the gearbox ?
My theory would be if it had a failed clutch it should slip but still change gear, do you have manual function on the gearbox and have you tried it out ?
Also not sure who is familiar with these GM Boxes.

 

[Gordvisr]

https://www.bimmerforums.co.uk/threads/2002-e53-x5-3-0d-sport-auto-trans-failsafe-mode.62880/

Might be some useful info here

 

[Gordvisr]

https://www.bimmerfest.com/threads/2002-x5-starts-but-wont-move-in-any-gear.917348/

Some more

 

[Solo Man]

The 2003 X5 3l diesel i bought from my brother broke its GM gearbox at about 135k kms. Had to be repaired and cost was about R18k iirc in 2010/12, not sure the year. He used to tow heavy trailers with it, so was no surprise when it packed up. When i sold it with about R200k kms on the odo it was still going fine. Not sure who fixed it as the car broke down in Mosselbay and my brother is deceased. I once had it serviced at ZF but not sure if they still do it.