66RFE Automatic Transmission Assembly for 2013-2018 Ram 2500, 3500

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

• Confirm truck is a heavy-duty Ram 2500 or 3500 with the 5.7L or 6.4L Hemi V8 engine (not diesel, not Ram 1500).
• Verify the transmission tag on the driver's side of the case reads 66RFE.
• Check cooler line fitting size if the truck is a 2013 model (1/2" vs 3/4").
• Confirm the truck is a 4x4 (four-wheel drive) and not a 2WD.

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

Special tools this job needs:

• heavy-duty transmission jack
• transfer case jack/adapter
• torque wrench
• professional-grade OBD2 scan tool with Chrysler-specific functions (e.g., WiTech, Snap-On Modis, AutoEnginuity, or AlfaOBD)

Budget for these consumables at install:

• Licensed Mopar ATF+4 (or equivalent fully synthetic ATF+4 meeting MS-9602 specification)
• Flat sump filter (with its rubber grommet/seal)
• Spin-on canister filter (metal threaded adapter upgrade recommended)
• High-quality RTV silicone sealant
• Front pump/input shaft seal (torque converter seal)
• Transmission cooler flush solvent / heated flush machine

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

What’s involved: TCM Adaptive Relearn ("Quick Learn")

You must perform a "Quick Learn" procedure immediately after installation before driving the vehicle to reset the Clutch Volume Indexes (CVIs). Driving without performing a Quick Learn can cause immediate, catastrophic clutch slippage and burn up the new transmission. A 300-mile "Drive Learn" period of gentle driving is also required.

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 transmission input shaft and pump gears (three distinct drops) before bolting the transmission to the engine to avoid crushing the front pump gear.
• Cooler Line Thread Split: Ram made a production split in mid-2013. Early 2013 cases have 1/2" threaded cooler line fittings, while late 2013 through 2018 cases have 3/4" threaded cooler line fittings. If installing this 2017 unit (3/4" threads) into an early 2013 truck, you must purchase adapter fittings (Mopar part # 68200538AA).
• The Plastic Filter Screw Trap: The threaded snout the spin-on filter screws onto is plastic from the factory. It is easy to cross-thread or overtighten and crack, causing pressure drops and delayed engagement.
• Thermal Bypass Valve: If the old transmission failed due to overheating, the thermal bypass valve in the cooler lines is likely clogged or stuck closed. Replace this valve or install an aftermarket bypass delete kit.

Easy to get right once you know them:

• Skipping the Quick Learn procedure before driving, which burns up the overdrive clutches within the first 10 miles.
• Using non-licensed "Global" or multi-vehicle ATF instead of licensed Mopar ATF+4, leading to torque converter shudder and harsh shifts.
• Overtightening the spin-on filter and cracking the plastic threaded adapter on the valve body.
• Using the bellhousing bolts to pull the transmission case up to the engine block instead of sliding it completely flush by hand.

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: