Remanufactured ZF 8HP valve body with the full solenoid set installed, disassembled, cleaned, calibrated and bench tested to OE form and function.
A ZF eight-speed that hangs between gears, slams the 2-3 or 4-5 shift, will not hold torque converter lock-up, or drops into limp mode with a pressure or ratio code almost always points back to one part: the valve body bolted under the pan. This listing is a remanufactured unit supplied with its full solenoid set already installed, so you are not pulling solenoids off your old core and hoping they test good. Every unit is disassembled, cleaned, inspected, calibrated and bench tested to OE form and function before it ships, which matters on an 8HP because the bores wear - a valve body that only got a wash and a new solenoid pack on top of worn bores will still hang shifts.
The 8HP skips the accumulator-spring hydraulics of older automatics for a fully electronic valve body. The transmission control module fires shift and pressure-control solenoids mounted in this casting, and those solenoids move spool valves through precision bores to route line pressure to the correct clutch pack for each of the eight forward gears and to the torque converter lock-up circuit. This reman unit covers the 8HP45, 8HP55, 8HP70 and 8HP90 family used across BMW, Audi, Land Rover and Jaguar - share the same outline and hydraulic layout, but not the same calibration, so the ZF code stamped on your old unit has to match before you order.
Sonnax documents bore and sleeve wear at the main pressure regulator as the most common failure across the whole 8HP45/8HP70/845RE family, and that wear bleeds fluid past the valve so line pressure drops throughout the unit - no amount of fresh fluid or a new solenoid pack fixes worn bores. Our valve body wear and bench fix guide covers how that failure presents on a scan tool, and our ZF8HP common problems guide walks through separating a worn valve body from a failing speed sensor or a fluid-level issue before you spend money on the wrong part.
Covers the ZF 8HP45, 8HP55, 8HP70 and 8HP90 eight-speed automatics behind BMW, Audi, Land Rover and Jaguar engines. The family shares an outline but the internal calibration is specific to the torque rating, so verify the ZF code stamped on your old unit and the casting number before ordering rather than going by engine size or model year alone - if you are not sure which casting your car has, send us the year, make and model and we will confirm it. Browse the full ZF 8HP parts collection if your application turns out to need a different family member.
On most of these vehicles the valve body and mechatronic unit come out together as an assembly once the pan is off and the internal wiring sleeve is released - do this with the fluid drained and the car supported properly. Replace the pan gasket and filter while access is open, and change the mechatronic sleeve seal at the same time since that seal is a known leak point on this family, covered in our mechatronic sleeve leak guide. Refill only with ZF LifeGuard 8 ATF and set the level by the temperature and overflow procedure, not a dipstick guess, then run the transmission control module's adaptive relearn so it calibrates clutch fill times against the new valve body instead of carrying over the old unit's adaptives. Pair the job with a cooler flush and, if your converter has not been tested, our ZF8HP pump and a fresh 7-liter LifeGuard 8 service fill so the whole hydraulic circuit is clean behind the new unit.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes. This is a remanufactured unit supplied with the full solenoid set already installed, calibrated and bench tested - you are not transferring solenoids off your old core.
The ZF 8HP45, 8HP55, 8HP70 and 8HP90 eight-speed automatics used in BMW, Audi, Land Rover and Jaguar applications. Verify your ZF code and casting number before ordering since the family shares an outline but not a calibration.
Harsh or flared shifts, slipping between gears, torque converter clutch shudder at cruise, or limp mode with a stored pressure, ratio or solenoid code.
Replace the pan gasket, filter and mechatronic sleeve seal while the unit is accessible, refill with ZF LifeGuard 8 ATF, and run the adaptive relearn afterward.
Only if the bores have not worn. If the pressure regulator bore is worn, a new solenoid pack alone will not hold line pressure - our common problems guide covers how to tell the difference.
This is a remanufactured unit tested to OE form and function before it ships; see the listing for the specific warranty term.
