Hot Shot's Secret Adrenaline ProShift+4 ATF+4 1 Gallon

Adrenaline ProShift+4 is a full synthetic ATF+4 fluid built to the Chrysler MS-9602 specification, which means it is the correct fluid for essentially every Chrysler, Dodge, Jeep, and Ram automatic transmission from roughly 1998 forward that calls for ATF+4. That covers the 42RLE, 45RFE, 545RFE, 65RFE, 66RFE and the 68RFE behind the Cummins, the 62TE and 948TE transaxles, and the Mercedes-sourced NAG1 (W5A580) used in many trucks and rear-drive cars. ATF+4 is a licensed, backward-compatible fluid, so it also replaces the older ATF+3 and ATF+2 calls.

ATF+4 is not a drop-in for a plain Dexron/Mercon transmission. It uses a specific friction curve that the Chrysler clutch packs and torque converter lockup are calibrated around, and running the wrong fluid is a common cause of shudder and harsh or flared shifts in these units. Using a fluid that actually meets MS-9602 is what keeps the converter clutch applying smoothly and the shifts crisp.

On the bench or under the truck this is a straightforward drain-and-fill: drop the pan or pull the drain plug, change the filter, refill through the dipstick tube or fill plug, then set the level off the hot marks with the transmission in the temperature window the service manual specifies (the 68RFE and NAG1 both want a checked temperature, not a cold guess). A gallon is four quarts; a pan drop on most of these takes four to five quarts, and a full flush takes considerably more, so order accordingly.

The reason to run a synthetic ATF+4 over a bargain fluid is heat. These transmissions live behind big torque and heavy loads, and heat is what kills the fluid and then the clutches. The synthetic base and extreme-pressure additive package hold their viscosity and film strength when a towing or performance transmission climbs in temperature, which is where a marginal fluid thins out and lets metal touch metal. Ships from the USA.