Transmission Heat Exchanger - E39 540i 99-03, E38 740i/iL 99-01

This part is listed by BMW as BMW part number 17217505823 (17-21-7-505-823) and is described as Transmission Heat Exchanger (Oil Cooler) for the E39 540i (1999, 2000, 2001, 2003, 2003) and E38 740i/740iL (1999, 2000, 2001). 

Not for cars before the 1999 model year. 

This air-to-oil heat exchanger is located behind the driver side fender liner, along the driver side frame rail. It can be hard to find at first, but is a common failure item on the M62TU V8 equipped model 5 series and 7 series, as well as the M73TU V12 powered 750iL. 

If you are having transmission temperature faults, hard or hesitation when shifting, it could be that this cooler has internally clogged or failed, increasing the oil temps of your transmission. The fix for this issue is a new heat exchanger / transmission oil cooler unit. 

For questions, BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.

BMW Fitments:

5 Series
E39 (97-03) > 540i
7 Series
E38 (95-01) > 740i
E38 (95-01) > 740iL
E38 (95-01) > 750iL