Great DIY, thanks for putting this up! I've seen quite a few posts about the Mechatronics sleeve leaking on the ZF gearboxes, and most people recommend changing the sleeve when dropping the pan. Is this a common problem on the GM transmission, or is this just an issue on the ZF units? Do the GM units have a Mechatronics sleeve?
I've got 120,000 miles on my 328i right now, and I'm not sure if the fluid has been changed previously. Really on the fence right now as to whether I should go ahead and drain & refill with new fluid, or drive it till the transmission dies. Can anyone who has done this on a higher mileage car chime in on whether they ran into any issues after the drain & refill?