68RFE Transmission Cooler, new and ready to install. Fits the 68RFE. Ships fast from the USA.
Owners of 2013-2018 Ram 2500 and 3500 trucks with the 6.7L Cummins and 68RFE often notice the transmission temperature gauge sitting higher than it did on older trucks, especially with a fifth wheel or gooseneck behind them. One reason is the factory thermostatic bypass in the cooler circuit. Read this before ordering: although this page is named transmission cooler, the part is not a cooler core. It is a new RevMax cooler thermostatic bypass upgrade, manufacturer part number 68RFE-929AA, which replaces the factory bypass module and sends fluid through your existing cooler full time.
On these trucks the fluid leaving the transmission passes through a thermostatic bypass before it reaches the cooler. When the fluid is cold, the factory valve routes it around the cooler so the transmission warms up faster; once it is hot, the valve is supposed to open and send fluid through the cooler. RevMax states that the factory part has two weaknesses. Its valve can stick in the cold, closed position, so fluid never reaches the cooler, and RevMax ties that failure to melted-down transmissions. And even when it works, it has an internal orifice that RevMax says reduces cooler flow by 87 percent. The RevMax module is machined from billet 6061 aluminum with cooling fins, made in the USA, and uses what RevMax calls ZeroStat design: the orifice and thermostat are eliminated so the cooler sees flow all the time.
With the truck at full operating temperature, carefully compare the temperature of the inlet and outlet lines at the cooler; if the cooler stays cool while the transmission is hot, the bypass is not opening. Then check flow. GEARS Magazine recommends disconnecting the return line into a bucket or using a flow meter and seeing at least a gallon per minute. The same ATRA article sets 200 degrees F as the ideal maximum fluid temperature and says every 20 degrees above that cuts transmission life in half. If flow is good and the truck still runs hot, look at load, engine cooling and the fan clutch. For the rest of the common failures on these trucks, read our 68RFE Ram 3500 Cummins common problems guide, and if heat has already caused shift complaints, see 68RFE valve body problems and testing.
RevMax lists this part for 2013-2018 Dodge Ram 2500 and 3500 with the 6.7L Cummins and 68RFE or Aisin AS69 automatic, and it also fits the 66RFE. It is a year-specific design: RevMax makes a different bypass for 2010-2012 trucks and another for 2019 and newer, and those are not interchangeable with this one. Check your model year and that your truck still has the factory bypass module before ordering, or send us your year and VIN and we will confirm. See everything we stock for this transmission on the 68RFE collection page.
RevMax says no lines are cut and nothing is altered; you disconnect the cooler lines from the factory bypass, remove it, and connect the same lines to the new module. Inspect the quick-connect fittings and their seals before reconnecting. Expect to lose some fluid, and refill with ATF+4 only, setting the level with the fluid at 160 degrees F or higher as the FCA procedure requires. Because the cooler now sees flow all the time, warm-up will take longer in very cold weather. If the fluid is already dark, change it and the filters at the same time; our 68RFE deep aluminum pan with filter kit adds fluid capacity for towing, and a truck with erratic line pressure may also need the 2013-2018 68RFE pressure control solenoid.
| Fits | 68RFE |
| Part type | Transmission Cooler |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is a thermostatic bypass upgrade, not a cooler core. It replaces the factory bypass module in the cooler circuit and works with your existing cooler.
2013-2018 Ram 2500 and 3500 with the 6.7L Cummins and the 68RFE or Aisin AS69, and the 66RFE. 2010-2012 and 2019-up trucks use different bypass designs.
Yes, somewhat, because the factory thermostat that sends cold fluid around the cooler is eliminated. In very cold climates expect a slower warm-up in exchange for full cooler flow under load.
No. The manufacturer states no lines are cut and nothing is altered. The existing lines unplug from the factory bypass and connect to the new module.
ATF+4 only. Top off any fluid lost during the swap and check the level with the fluid at 160 degrees F or higher.
If the transmission is hot but the cooler core and its return line stay cool, fluid is not reaching the cooler. A flow test at the return line under a gallon per minute also points to a restriction.
