8HP70 Transmission Solenoid Kit 9-Piece 1087-298-388

This is the nine-piece solenoid set for the ZF 8HP eight-speed mechatronic unit, replacing OE reference 1087-298-388. It covers the 8HP45, 8HP70 and 8HP90 variants of the ZF eight-speed, which is the box used under BMW, Audi, Land Rover and Jaguar and also sold in Chrysler applications as the 845RE and 8HP70 in Ram 1500, Grand Cherokee, Charger and Challenger. The solenoids ship remanufactured and flow-tested rather than raw rebuilt cores, which is why a set costs a fraction of a replacement mechatronic assembly.

On the ZF 8HP the solenoids live on the mechatronic unit inside the case, behind the combined pan and filter. You drop the fluid, unbolt the pan (the filter is part of it on this design, so it is replaced at the same time), then unplug and unclip the solenoids one at a time off the valve body. Change them one for one so you do not mix up locations, torque the pan bolts in sequence, and refill to the ZF fill procedure using the fill plug and the correct fluid temperature window. This transmission is temperature-sensitive on fill level, so do not eyeball it.

These are the parts to reach for when an 8HP comes in with harsh or banging upshifts, a flare between gears, delayed engagement into drive, shudder under light throttle, or the transmission dropping into limp mode with stored shift and pressure control faults. A single failed pressure solenoid will throw the whole shift schedule off, so the set is the sane repair once one has gone down. Confirm your unit is an 8HP45, 8HP70 or 8HP90 and that your solenoid body matches 1087-298-388 before ordering, since ZF changed hardware across the run.