ZF Lifeguardfluid 6 ATF for 6HP Transmissions, 6 Liter

This is ZF Lifeguardfluid 6, the automatic transmission fluid ZF specifies for its 6HP family of six-speed automatics. ZF's own part number is S671.090.255, and BMW sells the same fluid under OE number 83 22 2 220 445. It ships as six one-liter bottles, which is the volume a normal pan-drop and filter service actually consumes, so you are not stuck two bottles short with the pan already off.

Fitment is the ZF 6HP series: 6HP19, 6HP21, 6HP26, 6HP28 and 6HP32, in their rear-drive and all-wheel-drive forms. That covers a wide spread of BMW 3, 5, 6, 7 and X models from the mid-2000s on, plus Audi, Jaguar and Land Rover units built on the same case. Check the tag or the casting on your unit and confirm it is a 6HP before you fill. A ZF 8HP takes Lifeguardfluid 8, not this, and the two are not interchangeable.

On the job, the 6HP has no dipstick. You drop the pan, replace the pan-and-filter module, reinstall, then fill through the side fill plug with a pump until fluid runs back out with the transmission at operating temperature, generally in the 30 to 40 degree C window with the engine idling and the selector cycled through the gears. Level it hot, cap the plug, and check for weep at the pan seal.

The failures this fixes are the ones 6HP owners describe as the transmission getting old: a hard or delayed 1-2, flare on the 4-5, shudder at light throttle from a converter clutch riding on oxidized fluid, and the limp-mode codes that follow once the friction modifiers are gone. Burnt or dark ATF in a 6HP is a service item, not a rebuild sentence, if you catch it.