BMW E39 540i (Auto) Cant figure out where the leak is coming from

[dnkroz]

Hi guys, Ive been lurking bimmerforums for awhile but this is my first post lol. Ive been noticing some oil drops on the floor of my garage around the rear of the engine, so i jacked it up to see where it was coming from and saw this (refer to pics). Where could it be leaking from? is the transmission oil or engine oil? what seal could have gone bad? the car drives fine btw, as good as an auto 540i can be https://www.bimmerforums.com/images/smilies//1shifty.gif

Pics:
https://imgur.com/MMdxW74
https://imgur.com/oRYMiHd

[shogun]

Try to post the pics again. ATF is usually red, engine oil is darker, old one black. Power steering fluid has a different color.

[JimLev]

Can you host the pic somewhere and then past the URL here?

[dnkroz]

ok i even tried with imgur and still nothing lol. maybe this?

https://imgur.com/oRYMiHd

https://imgur.com/MMdxW74

- - - Updated - - -


Try to post the pics again. ATF is usually red, engine oil is darker, old one black. Power steering fluid has a different color.

its darkish brown, but ive seen ATF that hasn't been changed in a long time turn really dark so i wasn't sure

[DrCharles]

ATF and engine oil smell different too. Hard to describe but it's distinct.
Not sure about the tastes though ;)

[shogun]

Maybe the shaft seal of the transmission input shaft = shaft seal 24311422671 40x52x7, item 4 http://bmwfans.info/parts-catalog/E39-Sedan/Europe/540i-M62/R-A/feb2000/browse/automatic_transmission/a5s560z_lubrication_system#1422671_4
Pull #7 cap and see if ATF drops out of the bell housing http://bmwfans.info/parts-catalog/E39-Sedan/Europe/540i-M62/R-A/feb2000/browse/automatic_transmission/gearbox_mounting_parts

To install a new shaft seal the transmission has to be removed.
But first clean all, then pull the cap #7 and see if ATF comes out there.

Leaking seals on input and output shaft are quite common after so many years of operation. I already replaced my ones some years ago.

[geargrinder]

I cant believe you have both rubber plugs there, most of the time those are long gone at this point. That's not a particularly wet M62 undercarriage honestly.

You do have to look real carefully w/ these cars (and others TBH) because oil leaks will tend to blow down and backwards and disguise where its coming from. It looks a bit like maybe its seeping down from the round plug area, which might hint at rear main seal and engine oil in my book, but I agree w/ DrChuck, the smell test would be first to try to confirm what it is.