Transmission Filter Change....

Hello,
I just got my 5hp18 tranmission filter in the mail, so I was about to change it out, but now I have confused myself with all the info I have read. So I have no Idea when the PO changed the fluid, I am going to say it was probably 50K ago, but who the hell knows. So my question is should I change part of it, which seems to be safer, or all of it? Changing part of the fluid just requires empting the fluid, changing the filter and gasket. Then refilling the amount you drained out, correct? And the car doesnt have to be running? Anything else that has to be replaced?

car has to be running, level with trans about 95 degrees. Fill through the bottom til it pours back out. Dextron III is fine.

see http://www.europeantransmissions.com/
technical help BMW, detailed instructions there

Just curious on why the car has to be running.

because the transmission pump has to run and the trans fluid needs a certain temperature which is very important, see the details here
http://www.europeantransmissions.com...ansService.pdf

Thx for the links Shogun, I think my tranny needs a lookover too!

Ah got it. That was the part I think I was missing. Thanks for the info!

In case anybody misunderstands you fill it first till it runs out then start it up and run until up to temp and fill more if needed

Keep the drip tray underneath when it comes to removing the oil filter. You may be surprised at the amount of ATF it is holding back