8-Speed Automatic Transmission Assembly for 2018-2025 Dodge & Jeep • Durango, Grand Cherokee

A quick look at your own vehicle makes sure the right transmission shows up:

• Verify the 8th digit of the VIN to confirm the vehicle has the 3.6L Pentastar V6 engine.
• Confirm the vehicle is AWD / 4x4 (this unit will not fit RWD/2WD models).
• Locate the stamped ID tag on the rear driver's side of the original transmission case to confirm it displays 850RE or 8HP50.
• Match the Mopar OEM part number on the original transmission case (e.g., 68271049AC, RL271049AA, or RL348506AC).
• For Jeep Grand Cherokee, confirm the vehicle is equipped with a single-speed transfer case.
• For 2021-2022 Grand Cherokee, check the 6th digit of the VIN to confirm it is 'E' or 'F' (WK body style; does not fit WL body style).

What the install really takes — plan and budget with confidence:

Special tools this job needs:

• Heavy-duty transmission jack
• Stubby and flex-head ratcheting wrenches
• Swivel/universal impact sockets
• Fluid transfer pump
• OBD2 diagnostic scanner / bi-directional scan tool (wiTECH, AlfaOBD, or JScan with security bypass)

Budget for these consumables at install:

• Mopar 8 & 9 Speed ATF (Part #68218925AB) or ZF LifeguardFluid 8 (DO NOT USE ATF+4)
• Replacement plastic transmission oil pan assembly with integrated fluid filter and gasket
• Front pump / torque converter seal
• Transmission cooler-line flush solvent

What your vehicle’s computers will need after the swap:

What’s involved: TCM Adaptive Relearn (Quick Learn) and VIN-specific programming

The TCM is integrated into the valve body. You must either have a professional clone your original TCM data to the replacement unit, or reprogram the replacement TCM to match your vehicle's VIN to resolve the security handshake. Once installed, a TCM 'Quick Learn' procedure must be performed using a bi-directional scan tool to establish baseline clutch application pressures, followed by a specific adaptation drive cycle.

Pro tips for a smooth first start-up — hand them to whoever does the install:

• Torque Converter Seating: Ensure the torque converter is fully seated onto the input shaft and oil pump (must drop inward past two distinct clicks). If not fully seated, bolting the transmission to the engine will crush the internal oil pump gear, ruining the unit.
• Fluid Level Checking Procedure: The transmission has no dipstick. Fluid level must be checked via the fill plug on the side of the case with the engine running, vehicle perfectly level, and fluid temperature strictly between 86°F and 122°F (30°C to 50°C).
• Exhaust Y-Pipe Clearance: You must unbolt and pull down the exhaust Y-pipe slightly or detach it from the catalytic converters to gain clearance to remove the transmission or service the pan.
• Solenoid Positions: If servicing solenoids on the valve body, they must be returned to their exact original slots as the TCM learns the unique flow characteristics of each individual solenoid.
• Cooler Line Quick Connects: Ensure cooler lines are pushed in until they click and plastic assurance caps are snapped into place to prevent line pressure from blowing them off.

Easy to get right once you know them:

• Using the wrong fluid (such as standard ATF+4 or generic multi-vehicle fluid) instead of the required ZF Lifeguard 8 or Mopar 8/9-speed fluid.
• Checking the fluid level with the engine turned off, which causes severe underfilling and immediate clutch burnout.
• Forcing the bellhousing bolts to draw the engine and transmission together when the torque converter is not fully seated, which cracks the pump.
• Ordering a RWD/2WD unit or a unit from a different engine application (like a Ram 1500 or Wrangler) assuming all 850RE units are interchangeable.
• Skipping the TCM Quick Learn procedure, resulting in harsh shifting, slipping, and potential clutch damage.

Not issues with the units on this page — the manufacturer documented these for every transmission of this family, wherever you buy one. Handy for your installer: