68RFE ZeroStat Cooler Bypass Kit, Ram 2500/3500 6.7 Cummins

The 68RFE in 2013-2018 Ram 2500 and 3500 trucks with the 6.7L Cummins runs a thermal bypass valve in the transmission cooler circuit. When the fluid is cold, that valve blocks flow to the external cooler so the trans warms up faster. The trouble is the valve can stick or fail, and when it does it starves the cooler and cooks the transmission. This billet 6061 aluminum unit replaces the factory thermal valve so fluid circulates to the cooler at all temperatures.

With the thermal valve gone, cooler flow is on full time, which holds fluid temperature down under towing and heavy loads. RevMax rates it at roughly 87 percent more flow than the restrictive OE setup. The body has integrated cooling fins to shed a little extra heat, and because flow is never gated you keep steady pressure to the cooler.

It goes in the factory location on the transmission case. The kit includes the billet bypass, two O-rings, two retaining clips, and a cleaning cloth. Pull the old thermal valve, seat the new unit with fresh O-rings, and clip it in. Once it is installed you can also flush the cooler lines with room-temperature fluid instead of a hot-flush machine, since flow is no longer temperature gated.

Fits 2013-2018 Ram 2500 and 3500 with the 68RFE six-speed automatic behind the 6.7L Cummins. It is not for the 2019-up cooler design.