8-Speed Automatic Transmission Assembly for 2018-2024 Ram 1500, Classic

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

• Confirm the truck has 5-lug wheels (Classic DS body style).
• Verify the engine is a 5.7L Hemi V8 (8th digit of VIN is 'T').
• Confirm the vehicle is a 4x4 model with a transfer case.
• Locate the transmission ID tag on the case and verify it designates a ZF 8HP70 (option code DFK).

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

Special tools this job needs:

• Heavy-duty transmission jack
• Torx and E-Torx socket sets
• Transmission cooler line quick-disconnect tool
• Bidirectional scan tool (e.g., Autel MaxiSYS, Launch, AlfaOBD, or wiTECH 2.0)
• Secure Gateway Module (SGW) Bypass Cable (for 2018+ models)
• Engine support bar
• Long extensions and swivels
• Torque wrench

Budget for these consumables at install:

• Mopar 8 & 9 Speed ATF or ZF Lifeguard 8 fluid (DO NOT use ATF+4 or generic fluids)
• Replacement plastic transmission pan assembly (includes integrated filter, gasket, and new bolts)
• Front pump/input shaft seal (torque converter seal)
• Rear output shaft seal (where transfer case mounts)
• Professional-grade transmission cooler line flush agent

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

What’s involved: VIN-specific programming, TCM adaptive relearn (Quicklearn), and security/immobilizer re-marriage

The replacement TCM must be programmed with the vehicle's VIN and run through a Quicklearn adaptive reset. This can be done using a dealer-level tool (wiTECH 2.0) or advanced aftermarket tools like AlfaOBD/Appcar DiagFCA. A physical Secure Gateway Module (SGW) bypass cable is required on 2018+ models to write data. Alternatively, the buyer can swap their original, functional valve body/TCM into the replacement transmission to bypass programming.

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

• Torque Converter Seating: Must be fully seated onto the input shaft and pump gears (clicking/stepping back 3 times). Forcing the bellhousing bolts tight with an unseated converter will instantly crack the internal oil pump gear.
• Exhaust Clearance & Fill Plug Access: The fill plug is extremely close to the exhaust Y-pipe. Loosen the plug before securing the exhaust and use a low-profile hex tool.
• Fluid Level Check Procedure: No dipstick is present. The vehicle must be level, engine running, cycling through gears, and fluid temperature strictly between 86°F and 122°F (30°C to 50°C) when checking the fill hole trickle.
• Mechatronic Position Sensor Alignment: If swapping the original valve body, use guide pins and align the manual park lever linkage carefully to avoid a No-Start or stuck-in-Park condition.
• Starter Removal: Torque converter bolts are only accessible after removing the starter motor.

Easy to get right once you know them:

• Using the wrong fluid (such as Mopar ATF+4), which causes immediate clutch slippage and failure.
• Ordering for a New-Body (DT) Ram with 6-lug wheels instead of the Classic (DS) Ram with 5-lug wheels.
• Skipping the mandatory transmission cooler and line flush, which pumps old debris into the replacement unit and voids the warranty.
• Forgetting to install a physical Secure Gateway Bypass harness on 2018+ models when attempting to program with AlfaOBD.
• Improper torque converter installation leading to a cracked front pump.
• Ignoring the precise temperature-based fluid level check procedure.

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: