Replaces the restrictive factory 68RFE thermal bypass so ATF reaches the cooler right away, cutting heat on 2013-2018 Ram 2500 and 3500 6.7L Cummins.
Owners of 2013-2018 Ram 2500 and 3500 trucks with the 6.7L Cummins and 68RFE usually find this part one of two ways: the transmission runs hotter than it should on the highway or with a load, or a shop tells them the cooler cannot be flushed properly because the factory thermal valve will not open. This is the RevMax 68RFE-929AA thermal bypass upgrade, a billet 6061 aluminum block that takes the place of the factory thermostatic valve and keeps the cooler in the circuit from the moment the engine starts.
In the stock 68RFE cooler circuit, returning fluid meets a thermostatic valve before the cooler. Cold fluid is turned back to the transmission so it warms faster; hot fluid is supposed to be sent through the cooler. GEARS Magazine points out two consequences of that design. First, a valve stuck in the bypass position leaves the cooler out of the loop, so the transmission overheats even with a healthy cooler. Second, a stuck valve means a flush machine will not clean the cooler at all, because fluid never reaches it. The RevMax block removes the valve and its internal restriction, so the cooler sees flow at any temperature. RevMax rates the gain at about 87 percent more flow than the factory part.
A bypass will not cure a plugged cooler, a kinked line or a fan clutch that never locks. Inspect the lines, confirm the viscous fan engages, and measure cooler return flow; GEARS uses one gallon per minute as the minimum. If the truck also has harsh or erratic shifts, low line pressure or codes, look at our 68RFE valve body testing guide and the Ram 3500 Cummins common problems guide before blaming heat alone.
Built for the 68RFE behind the 2013-2018 Ram 2500 and 3500 6.7L Cummins. The listing notes that owners have also fitted it to trucks labeled 66RFE, which is the same six-speed family; confirm your truck has the 2013-2018 bypass design before relying on that. It does not fit 2010-2012 or 2019-up trucks, which use different bypass parts. When in doubt, match your factory bypass block to the product photos or send us your year and VIN. Browse everything else for this transmission on the 68RFE collection page.
Pairing this with more fluid capacity helps on a hard-working truck; our cast aluminum 68RFE pan kit adds a finned deep pan with fresh filters. If heat has already damaged the clutches, a 68RFE master rebuild kit is the right next step.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes. The 68RFE-929AA is the RevMax ZeroStat thermostatic bypass for 2013-2018 trucks. It removes the thermal element and restriction so the cooler always gets flow.
Yes. With the thermal valve gone, flow through the cooler no longer depends on fluid temperature, so room-temperature fluid will pass through and clean it.
Some owners report it fits trucks labeled 66RFE, which is part of the same family. Confirm your truck is a 2013-2018 build with this style of bypass, or send us your VIN.
Only what drains from the lines and the old valve when they are disconnected. Top off with ATF+4 afterward and set the level with the transmission at operating temperature.
No. It replaces only the thermostatic bypass. If the cooler itself is plugged or leaking, it still needs repair or replacement.
