ZF 6HP26/6HP28 Transmission Oil Pan & Filter Kit, BMW GA6HP26Z

On the ZF 6HP26 and 6HP28 six-speed automatic the filter is not a separate screw-in element, it is molded into the plastic oil pan, so a proper fluid service means dropping the pan and installing this whole pan-and-filter unit. This is the genuine ZF part, OE number 24152333903, replacing the earlier 24117571227 and 24117522923 pans. ZF is the company that actually builds the transmission, so this is the same pan the dealer installs at a lower cost than the BMW-boxed version.

This is the fix when a high-mileage BMW starts thumping on the 1-2 or 2-3 upshift, holds gears too long, or flares between shifts. BMW calls the fluid and filter a lifetime fill, which in practice means the fluid burns and the filter loads up around 80,000 to 100,000 miles and the trans starts shifting hard. Dropping this pan, refilling with the correct 6HP-spec fluid (roughly 7 liters of ZF Lifeguard 6), and resetting the adaptations brings the shifts back.

Fitment covers the GA6HP26Z / GA6HP28Z family: BMW 5, 6 and 7 Series, X3 and X5, and the 335d (which uses the 6HP28), plus Audi A6, A8 and Q7, Jaguar S-Type, XF and XJ, and VW Phaeton running the same ZF gearbox. Note this pan kit does not include the valve-body sealing sleeve 24347558725 or the pan bolts; with the pan down it is smart to replace those sleeves and the internal mechatronic seals at the same time, since they are usually weeping by the time the fluid is due.