8-Speed 850RE Automatic Transmission Assembly for 2019-2024 Ram 1500

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

• Confirm the vehicle has the 3.6L Pentastar V6 engine (check emissions label under hood).
• Confirm the vehicle is a 4x4 model (verify presence of front driveshaft and transfer case).
• Confirm the vehicle is a 'New Body Style' (DT generation) with 6-lug wheels.
• Locate the transmission sales code 'DFT' on the driver's side door jamb sticker.

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

Special tools this job needs:

• Heavy-duty transmission jack
• Vehicle lift or high-clearance jack stands
• Swivel sockets and long extensions
• Fluid transfer pump
• Bi-directional scan tool (wiTECH 2.0, Autel MaxiSYS, or AlfaOBD) with security gateway bypass

Budget for these consumables at install:

• Mopar ZF 8 & 9 Speed ATF (Mopar Part # 68218925AB) or ZF Lifeguard 8 (approx. 8.5 to 9.0 quarts for dry fill)
• Complete Transmission Pan & Filter Kit (filter is permanently integrated into the plastic pan, includes new gasket and bolts)
• Torque Converter Input Seal (front pump seal)
• Professional Transmission Cooler-Line Flush solvent/kit

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

What’s involved: VIN-specific programming and Transmission Quick Learn (adaptive relearn)

The integrated TCM holds the donor vehicle's VIN and adaptive clutch values. The replacement TCM must be programmed with the recipient vehicle's VIN to prevent communication fault codes (U-codes) and limp-home mode. A Transmission Quick Learn routine must also be executed to reset adaptive memory to match the replacement unit's clutch tolerances.

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

• Fluid level check must be performed strictly within the temperature window of 30°C to 50°C (86°F to 122°F).
• The engine must be running in Park during the fluid level check to prevent fluid drain-back and severe underfilling.
• The torque converter must be fully seated onto the input shaft and pump gears (three distinct 'clicks' or drops) before bolting to the engine to avoid cracking the pump gear.
• Ensure the old filter O-ring is removed from the transmission case to prevent a double O-ring seal failure, which causes air suction and clutch destruction.
• The plastic oil pan bolts must be torqued in a specific criss-cross sequence to exactly 10 Nm (88 in-lbs) to prevent warping and leaks.

Easy to get right once you know them:

• Using standard Mopar ATF+4 or generic multi-vehicle fluids instead of the required ZF 8-speed spec fluid.
• Assuming 2WD and 4x4 transmissions are interchangeable (they have completely different output shafts and tailhousings).
• Attempting to install this 850RE transmission on a 5.7L Hemi V8 engine.
• Skipping the TCM adaptive relearn / Quick Learn process, leading to immediate harsh shifting or transmission damage.
• Failing to professionally flush the transmission cooler lines, which washes old metallic debris directly into the replacement unit.

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: