Spring is the best time to run through your drivetrain. You've come off a winter of cold starts, road salt, and if you're in a towing application, likely some early-season work. Here's the checklist I run through for RAM and Dodge drivetrain owners every spring — transmission, transfer case, differentials, and the scanning piece that ties it all together. Do this once and you'll head into summer towing season with confidence. Pull the transmission fluid and evaluate condition. Warm the truck up fully before checking level. For the 68RFE, 45RFE, or 545RFE, you're looking for ATF+4 that's still red and clean-smelling — not brown, not dark, not gritty. If you towed heavily last season and haven't serviced since fall, do a drain-and-fill now before the heat of summer. The 68RFE especially runs hotter under load than most owners expect, and degraded ATF+4 at the start of towing season compounds fast. If you have the ZF 8HP in a RAM 1500 or Grand Cherokee, verify the fluid is ZF-spec Mopar 8&9 Speed ATF — not ATF+4. These are different fluids for different transmissions. Running ATF+4 in an 8HP is a common service error.
Recommended Products
Mopar ATF+4
Search AmazonSpring fluid service fluid for the 68RFE, 45RFE, 545RFE, and RAM/Durango transfer cases. Pick up 8 quarts for a transmission drain-and-fill plus enough for a transfer case top-off. If you towed last season and the fluid is due, do the service before summer towing season begins — not after.
Check Price on AmazonBlueDriver Bluetooth OBD2 Scanner
$89.95Run the spring scan on your RAM or Dodge with full Chrysler-enhanced code access. Reads pending codes the check engine light won't show yet — P0731 through P0736 slip codes, P0745 solenoid codes, and all TCM sub-codes under P0700. The live data mode also shows TFT so you can establish a baseline transmission temperature before towing season loads the drivetrain.
Check Price on AmazonRoyal Purple Max-Gear 75W-140
$22.97Differential fluid for RAM 2500/3500 rear axle in towing applications. The AAM 11.5-inch rear axle in heavy-duty RAM trucks specifies 75W-140 for towing — this is not interchangeable with 75W-90. Royal Purple Max-Gear meets the API GL-5 spec required for AAM axles and is a quality spring differential service fluid. Verify your axle application before ordering — 2500/3500 tow rigs typically need 75W-140 rear, 75W-90 front.
Check Price on Amazon