8HP90 8-Speed Overhaul & Seal Kit (BMW, Audi, Jaguar, Land Rover)

This is an overhaul and reseal kit for the ZF 8HP90, the heavy-duty version of ZF's eight-speed automatic used behind the larger engines from BMW, Audi, Jaguar and Land Rover. It carries the full set of external and internal seals you replace when the unit is apart: the pan gasket, the mechatronic sleeve and adapter seals, clutch drum sealing rings, the pump and output seals, and the O-rings and bonded pistons’ lip seals that ride on the drums. If you are tearing an 8HP90 down for a reseal, a leak repair, or a full rebuild, this is the soft-parts package that goes back in.

The 8HP90 shows up behind high-torque applications - BMW M-cars and larger sixes and eights, Audi with the ZF eight-speed longitudinal box, and Jaguar and Land Rover V8s. It is the same family as the 8HP45, 8HP55 and 8HP70 but built to hold more torque, so use a kit called out specifically for the 90 rather than a lighter-duty version. Confirm your ZF part number and build against the seals in the kit before you commit, since ZF revised sealing rings across production years.

On the bench the usual failure points are the mechatronic sleeve seals and the drum sealing rings, which harden and let pressure bleed off - that is what gives you the delayed or flared shifts owners complain about on these transmissions. Reseal it as a set, not one leak at a time: replace every ring the kit provides, lube the new seals with clean ATF on assembly, and refill with the correct ZF Lifeguard 8-speed fluid to level and temperature. This is a soft-parts overhaul kit; it does not include friction plates, steels, or hard parts. Ships from the USA.