Transmission Fluid low causing my stall when cold? Help ready to sell!

[02BMWX5]

Ok so i have this 2002 X 5 3.0 with 142,000 miles on it

I have replaced O2 sensors, Oil crankcase seperator, PCV valve, Idle control valve and nothing has fixed the issue

Here is my thought process:

My X5 when started cold wants to stall in reverse or drive and the rpm's drop below 500 rpms.

When the car warms up to normal temp say 10 min of driving it will not duplicate it.

Meaning it's fine and the truck runs fine and no slipping or nothing

Only when it's a cold start and I back out of the garage rpms drop and it wants to stall

Could it be something where the fluid is low or dirty and when the car warms up it breaks up or something?

Could a possible trans fluid change fix this issue?

I would think if it was a tranny issue I would have more issues than this?

Please help

Thanks