ZF8HP Shift Kit, new and ready to install. Fits the ZF8HP. Ships fast from the USA.
If your BMW, Ram, Charger, Grand Cherokee or Audi with the ZF 8-speed has started shifting harsh one day and soft the next, setting torque converter clutch codes, or chewing up converter lining, the problem is often worn valves and bores in the mechatronic valve body rather than the clutches themselves. This is a new TransGo shift kit for the first-generation ZF 8HP family. Unlike an old-school shift kit that simply raises pressure, this one is a valve body repair kit: it replaces the valves that wear in service so the TCM gets back the pressure control it was calibrated for.
Every gear in the 8HP comes from applying three of five elements (brakes A and B, clutches C, D and E), each controlled by its own pressure control solenoid in the Bosch mechatronic unit. TransGo's instructions label them N215 (A), N216 (B), N217 (C), N218 (D) and N233 (E), with N371 for the converter clutch and N443 for line pressure. Those solenoids only work if the regulator valves downstream can hold pressure. As the aluminum bores wear, line pressure, the solenoid feed (AFL) pressure and the converter clutch circuit all drift, and the TCM chases the drift with adaptations until it runs out of range. TransGo's kit for these units (SK 8HP) addresses exactly those circuits: a redesigned pressure regulator valve with a calibrated spring and bushing, a drop-in TCC regulator valve and spring, an oversized pressure reducing (AFL) valve and spring, an optional oversized converter pressure regulator valve, two end plug retainers and seven solenoid damper rubber inserts.
Do the basics first: verify the fluid level at the correct temperature, check for stored codes, and confirm the latest TCM software is installed, because both BMW and Chrysler released software fixes for 8-speed shift complaints. Then test the solenoids; Sonnax puts a good 8HP45/70 solenoid at about 5 to 6 ohms. If the solenoids pass and the complaint matches a worn circuit, the valve body is the repair. Our ZF8HP harsh shift causes guide and ZF8HP shift solenoid symptoms guide help separate a bad solenoid from a worn bore.
The kit fits the Gen 1 ZF 8HP45, 8HP55, 8HP70 and 8HP90 and the Chrysler 845RE. It does not fit the Gen 2 8HP50, 8HP75 or 8HP95 or the Chrysler 850RE. TransGo's quick check: Gen 1 units have valves in the upper valve body casting, Gen 2 units do not. Many vehicles changed generations partway through a model run, so look at the upper casting or read the tag on the case before ordering, and send us your year and VIN if you are unsure. Browse the full range on our ZF 8HP parts page.
| Fits | ZF8HP |
| Part type | Shift Kit |
| Condition | New |
| Brand | TransGo |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Not in the race-kit sense. It is a valve body repair kit that restores correct regulator pressures, so a worn unit shifts the way it was calibrated instead of harsh or soft. The TCM still controls shift feel.
Only if the transmission is a Gen 1 unit. The kit does not fit the Gen 2 8HP50, 8HP75, 8HP95 or 850RE. Gen 1 units have valves in the upper valve body casting; check that or send us your year and VIN.
Yes for two parts. The oversized AFL valve needs TransGo reamer kit ZF8-AFL-TK, and the optional oversized converter regulator valve needs ZF8-TCREG-TK. The other pieces drop in.
It targets them. The kit replaces the TCC regulator valve and offers an oversized converter pressure regulator valve, which addresses worn TCC circuits. A converter that is already damaged still needs replacing.
ZF LifeguardFluid 8 or the approved OEM 8-speed equivalent. Set the level with the transmission at 30 to 50 C using the overflow method, then reset and relearn adaptations.
