1989-1993 Dodge 5.9L Cummins Transmission Fluid

Transmission fluid for the 1989-1993 RAM 5.9L Cummins

Here's what each factory gearbox calls for. The Getrag G360 5-speed manual, used all five years, takes 3.5 quarts of 5W-30 motor oil with a drain and refill every 60,000 miles. The A727 TorqueFlite 3-speed automatic, used from 1989 to mid-1991, runs ATF+4, with fluid, filter and a band adjustment every 24,000 miles or 24 months. The A518 4-speed overdrive, sold as the 46RH from 1992, holds 14.5 to 16.5 quarts of ATF+4. The easy mistake is the manual: G360 fluid is motor oil, not gear oil and not ATF.

Heat, towing and fluid

Fluid temperature sits at the center of a lot of first-gen transmission trouble. On the G360, extended towing heats the fluid and starves the upper input bearing, which is why many owners run 15W-40 and add a quart over spec; that's owner practice, not the factory number. On the automatics, overheated fluid travels with slipping, a 2-3 flare and converter shudder on worn A518/46RH units, and rusted factory steel cooler lines leak the level down until the fluid burns. If what comes out looks or smells burnt, find out why before you simply refill.

What we carry

• ATF+4 labeled: Hot Shot's Secret Blue Diamond ATF+4/DEXRON III/MERCON V, the label that names the factory call-out for both first-gen automatics.
• ADRENALINE line: Hot Shot's Secret ADRENALINE Nano Shift, Speed Shift and Pro Shift +4.
• Additive: Hot Shot's Secret Shift Restore Transmission Fluid Additive.
• Other specs: Hot Shot's Secret Blue Diamond Type F, Blue Diamond Dexron VI and Mercon LV, and Blue Diamond G56 Severe Duty SAE 50.
• Multi-vehicle ATF: Lucas Oil 10418 Multi-Vehicle Automatic Transmission Fluid.

Fitment notes

Match the bottle to your transmission, not just to the truck. This page gathers fluids for more than one kind of transmission, and some bottles are named for other specs. For an A727 or A518/46RH, buy a fluid whose label calls out ATF+4. None of the ATFs here are the G360 spec. The G56 Severe Duty fluid is named for the G56, which only lives in a first gen that has been converted. And confirm which automatic you have: the A518 arrived mid-1991, so a 1991 truck can have either.

Frequently asked questions

Can I put ATF in my G360 manual?

No. The G360 is spec'd for 3.5 quarts of 5W-30 motor oil, not gear oil and not ATF. Many owners who tow run 15W-40 and overfill by a quart to protect the input bearing, but that's owner practice rather than the factory spec.

How much ATF does my automatic take?

The A518/46RH holds 14.5 to 16.5 quarts of ATF+4 in total. A pan drop and filter change takes less than that, and a deep pan adds capacity. The A727 also takes ATF+4; plan its fluid change with the filter and band adjustment every 24,000 miles or 24 months.

Which Hot Shot's Secret fluid should I use?

For a stock A727 or A518/46RH, start with a bottle that names ATF+4, such as the Blue Diamond ATF+4/DEXRON III/MERCON V. The G56 Severe Duty SAE 50 is for G56-converted trucks, not the G360. If you're unsure which bottle matches your truck, call the shop and we'll sort it out.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.