Pure Drivetrain 8HP50 High Performance Transmission Hard Parts Kit - AWD - Stage 2

The ZF 8HP50 is the second-generation 8-speed that replaced the 8HP45 starting around 2014. In all-wheel-drive BMWs it is coded GA8HP50X and sits behind engines such as the B46/B48 four-cylinder and the B58 six in F-series xDrive cars like the 340i xDrive, the F15 X5 and the early G01 X3 and G02 X4. Chrysler, Dodge and Jeep build their version of the same family as the 850RE. With a tune, the B58 in particular makes far more torque than ZF rated this case for, and the clutches are what pay for it. The Pure Drivetrain Solutions 12-96-2000 is the Stage 2 hard parts kit for the AWD 8HP50, for the builder who is opening the transmission and wants it to hold real power afterward.

How this kit strengthens an AWD 8HP50

Pure Drivetrain lists the 8HP50 at up to 500 Nm of input torque from the factory. Inside, five shift elements (two brakes, three clutches) are applied two at a time to make eight forward gears, which means a single weak clutch pack shows up as slip in several gears. The HPK goes after that weak point with Pure Drivetrain's FSR friction plates, C6X steels and pressure plates, and billet 7075 aluminum hubs that are heat treated and hard anodized. The company says the hubs gain extra oil passages for cooling and fluid distribution, revised tooth profiles on the clutch packs and mating parts, and a longer base shoulder to support the clutch base plates. Stage 2 is the higher holding-capacity version of the kit.

What a worn 8HP50 does

• Shifts that flare or slip under boost, especially once the fluid is up to temperature
• A harsh or pushing feel on shifts as pressure drops; Pure Drivetrain names solenoids clogged by friction wear as the main 8HP50 problem
• Vibration from the transmission that, left alone, can break the oil pump bearing
• Cracked or burst aluminum drums after hard launches, which Pure Drivetrain lists as a common failure under aggressive driving
• Leaks at bushings and rubber seals, the weak spot the company calls out across this family

Confirm the diagnosis first

Set the fluid level hot using ZF's procedure before you condemn anything; a low 8HP50 slips and shifts poorly on its own. Then scan for transmission faults and check the adaptations. Because solenoid contamination is so common on this unit, a pressure fault in the valve body can mimic a burned clutch, and a hard parts kit will not fix it. The ZF8HP pressure control solenoid guide explains how to separate the two. Jeep owners should also read the Jeep Grand Cherokee 8-speed shift problems guide, and BMW owners the BMW 3 Series 8-speed common problems guide.

Fitment

This listing is the AWD ZF 8HP50. It is a second-generation case, so first-generation 8HP45 internals do not carry over, and GEARS Magazine notes that Gen 1 valve body kits are not listed for the Gen 2 8HP50 either. Pure Drivetrain lists AWD-capable 8HP50 applications including F-series BMW xDrive models from 2014, the Alfa Romeo Giulia and Stelvio Q4, and the Jeep Grand Cherokee WK2 from 2017. Many of the same vehicles were also built with an 8HP75 or 8HP70, and the later G-series BMWs moved to the 8HP51, so the case tag is what decides this. If yours reads 8HP51 with xDrive, order the 8HP51 AWD Stage 2 kit. Send the tag reading, year and VIN before ordering; Pure Drivetrain requires fitment confirmation. Everything else for the 8-speed is on our ZF 8HP collection page.

Install notes

• Full disassembly is required. Replace all seals and bushings while it is apart, since those are the family's known weak points, and inspect every drum.
• Clean the cooler and converter and, on AWD vehicles, drain the transfer case if it shows contamination. Pure Drivetrain calls for all three before break-in.
• Fit a new pan with its bonded filter; the ZF 8HP pan and filter kit lists the 8HP50.
• Fill with ZF LifeguardFluid 8 or a Pure Drivetrain approved fluid and check the level hot per ZF. Low fluid is the most common reason a fresh build will not shift right.
• Begin with a known-good calibration, reset adaptations and run the quick learn, then 500 miles of stop-and-go driving through all the gears before any full-load pass.

Will this fit my 2018 BMW 340i xDrive?

F30 340i xDrive cars use the AWD 8HP50 in most cases, which is what this kit is listed for. Confirm with the ZF tag on the case and your VIN before ordering.

Does it fit a Jeep with the 850RE?

Some Jeep 850RE transmissions are 8HP50-based and some are 8HP75-based. Send the case tag reading and VIN so the right kit can be matched.

Can I use 8HP45 parts in an 8HP50?

No. The 8HP50 is a second-generation case and Gen 1 internals and valve body kits are not listed for it. Buy parts listed for the 8HP50.

What comes in the kit?

FSR friction plates, C6X steels and pressure plates, and heat treated, hard anodized billet 7075 hubs. Seals, gaskets, filter and fluid are separate.

What fluid and break-in does it need?

ZF LifeguardFluid 8 or a Pure Drivetrain approved fluid, set hot. Then reset adaptations, run the quick learn and drive 500 miles of stop-and-go before full power.

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