Ram 6.7L Cummins Thermal Bypass Valve Upgrade Guide: ATS vs PPE vs BD for 2010-2024 Trucks

If your 6.7L Cummins Ram climbs past 200 degrees on the transmission temp gauge every time you hook up a trailer, the problem is usually not the cooler and it is not the fluid. It is a small thermostatic valve in the cooler line that Ram has used on every 68RFE and Aisin since 2010 to speed up warm-up, and it is holding your fluid out of the cooler when you need it most. Here is how it works, why it fails, which upgrade fits your year, and how to install it in an afternoon for about the price of a fluid change.

Why the 68RFE and Aisin run hot transmission temps when towing

Every 6.7L Cummins Ram since 2010 was sold as a towing truck first, and the newest ones are rated well past 20,000 pounds with the right axle and transmission. Owners buy them for exactly that, and then watch the transmission temperature reading climb into the 210s and 220s on a long grade with a fifth wheel behind them. The truck is not defective. It is doing what the cooling circuit was designed to do, and that design was optimized for warm-up speed, not for sustained heavy load.

Both transmissions offered in these trucks, the 68RFE behind the standard output Cummins and the Aisin AS69RC behind the high output engine (2013 and newer), use a thermal bypass valve in the cooler line circuit. The valve contains a wax-element thermostat, similar in concept to your engine thermostat. When the fluid is cold, the valve stays closed to the cooler and the fluid loops straight back into the transmission. That gets the fluid up to operating temperature faster, which helps fuel economy and shift quality on cold starts. Once the fluid reaches the valve's opening point, it is supposed to open and send fluid through the external cooler.

Two things go wrong with that design in the real world:

• The valve sticks. Wax-motor thermostats are a wear item. Over time the element can hang partially closed, so the cooler only sees a fraction of the flow it was sized for. The gauge creeps up on every tow and the owner starts shopping for a bigger cooler that will not fix anything, because the fluid is not reaching the cooler it already has.
• Even a healthy valve is a restriction. The valve is a small passage in a cast block, and even fully open it is a choke point compared to a straight-through path. Under sustained load with high line pressure and a torque converter that is generating a lot of heat, that restriction costs cooling capacity right when you need all of it.

The result is a transmission that runs 15-30 degrees hotter than it needs to under load. That matters more than most owners realize.

What hot fluid actually costs you

ATF+4 is a good fluid, but it has limits. The general rule that transmission builders use is that fluid life is fine below about 200 degrees, degradation accelerates noticeably above 220, and every sustained 20 degree step above that roughly halves the life of the fluid and the clutches soaking in it. A 68RFE that spends every summer tow at 225 is not going to fail tomorrow, but it is aging faster than the odometer says, and the 68RFE is not a transmission you want to rebuild early. Clutch material, valve body wear, and torque converter clutch life all track directly with fluid temperature.

The Aisin is stouter, but it is not immune, and it is bolted to the high output engine that makes the most heat. If you tow at or near the truck's rating, keeping the Aisin in its comfort zone is cheap insurance on a very expensive component.

How a full-flow bypass block fixes it

Every upgrade in this guide does the same fundamental thing: it replaces the factory thermostatic valve block with a machined aluminum block that has no thermostat in it at all. Fluid goes to the cooler 100 percent of the time, from the moment you start the truck. There is nothing to stick, nothing to wear, and no restriction. Each one bolts into the factory location on the passenger side of the transmission using the factory cooler lines, so there is no cutting, no tuning, and no special tools. The differences between brands come down to what else is in the box, warranty, and price.

Which thermal bypass valve fits your Ram: 2010-2024 by year

Ram changed the valve block design twice, so the part number depends on your model year. Here is everything we carry, with our pick for each generation.

Prices as listed on alligatorperformance.com at time of publishing and subject to change. All parts fit 2WD and 4WD.

2019-2024: why the ATS is worth the extra $28

The ATS 310-005-2464 adds one thing the other valves on the market do not: a billet filter coupler for the 68RFE. The 68RFE uses a threaded spin-on filter inside the pan that screws onto a plastic coupler in the valve body. That plastic coupler is a known weak point; it can crack or strip when the filter is changed, and a damaged coupler means unmetered fluid bypassing the filter. ATS includes a billet aluminum coupler that replaces it permanently. If you were already planning a fluid and filter service, this is the time to do both. The valve is CNC-machined billet, made in the USA, and backed by a lifetime warranty. It fits 2019-2024 Ram 2500, 3500, 4500 and 5500 with the 6.7L Cummins and either the 68RFE or the Aisin AS69RC. The billet filter coupler applies to the 68RFE only; Aisin trucks use the valve block alone, which is why the $72 PPE 225065100 is the smarter buy for a high output truck. Note that the ATS part is not legal for sale or use in California.

2013-2018: the PPE is the one we sell most, and for good reason

Fourth-gen owners have the most choices, and the PPE 225065000 outsells everything else on this platform for a simple reason: it is a billet full-flow block at $72 that fits both the 68RFE and the Aisin AS69RC, and there is nothing else you need. The ATS 310-005-2392 does the same job with a lifetime warranty for $28 more; on this generation ATS does not include the filter coupler, so the decision is warranty versus price. The BD 1061528, Randy's Juice Box and RevMax ZeroStat are all solid and make sense if you already run that builder's transmission and want to keep the paperwork in one place.

2010-2012: two options, both good

The 2010-2012 trucks were the first 68RFE Rams with a thermal bypass valve in the cooler circuit and they use their own block. The ATS 310-005-2356 is the billet, lifetime-warranty option at $99.99, and the RevMax 68RFE-929A is a proven alternative at $89.10 from one of the best-known 68RFE builders in the country. If you have a 2007.5-2009 truck, your cooler circuit does not use this valve, so a deep pan and a larger cooler are your upgrade path.

How to install a thermal bypass valve upgrade

This is a driveway job and the procedure is the same for every brand and every year. The valve block is on the passenger side of the transmission where the two cooler lines enter. Budget about an hour for the valve and another hour if you are dropping the pan for the ATS filter coupler on a 2019-2024 truck. Torque specs below are from the ATS manual; check your kit's instructions if they differ.

Tools you need

• 1 inch wrench (or a large adjustable) and a 20mm wrench for the cooler line nuts
• 10mm socket for the retaining plate bolt
• 1/2 inch Allen for the pan drain, filter wrench, gasket scraper and razor blade if doing the coupler
• Drain pan and shop towels; you will lose some fluid when the cooler lines come off
• Roughly 5 quarts of ATF+4 if you are dropping the pan

Valve block install

1. Locate the factory thermal bypass block on the passenger side of the transmission and put a drain pan under it.
2. Loosen and remove the two cooler line fittings. Expect fluid; let it drain into the pan.
3. Remove the 10mm retaining plate bolt and pull the factory valve block.
4. Install the new O-rings on the ATS block and lubricate them with clean ATF+4.
5. Seat the ATS block, reinstall the retaining plate and torque the bolt to 13 ft-lbs.
6. Reconnect the cooler lines and torque the nuts to 20 ft-lbs.
7. Start the truck, check for leaks at the block, then top off fluid to the correct level on the dipstick procedure for your transmission. Recheck for leaks after the first drive.

Billet filter coupler install (ATS 310-005-2464, 68RFE only)

1. Drain and drop the transmission pan. Remove the primary sump filter and the screw-in spin-on filter.
2. Remove the factory plastic coupler and thread in the ATS billet coupler.
3. Install a new spin-on filter and torque to 84 in-lbs. Install the new primary filter and torque the bolt to 40 in-lbs.
4. Clean both sealing surfaces completely dry, apply RTV per the ATS instructions or use your pan gasket, and torque the pan bolts to 110 in-lbs.
5. Refill with ATF+4, run through the gears, and set the level hot.

ATS and PPE both publish installation instructions with photos; they are worth reading once before you start. The whole job is well within reach of anyone who has done their own transmission service.

One honest trade-off: cold weather warm-up

The factory valve exists for a reason, and removing it means the transmission takes longer to reach operating temperature on cold mornings because the fluid is going through the cooler from the first mile. In Texas, Arizona or the Southeast this is a non-issue. If you are in Minnesota or Alberta and the truck sits outside at minus 20, expect slightly firmer shifts for the first few minutes until the fluid warms, and consider whether you want full-time cooler flow year round. For the overwhelming majority of owners who bought these trucks to tow, the trade is worth it many times over. A transmission that warms up two minutes slower in January and runs 25 degrees cooler in July is a transmission that lasts.

What to pair it with

The bypass valve is the first thing to do because it is the cheapest and it fixes the actual bottleneck. Once fluid is flowing through the cooler full time, the next upgrades make a real difference instead of a theoretical one:

• Deep transmission pan. More fluid capacity means more thermal mass and slower temperature swings on a long grade. The PPE and RevMax deep pans for the 2019-2024 Ram and the RevMax deep pan for 2007.5-2018 add capacity and a proper drain plug, and a pan drop is the right time to service the filters anyway.
• Upgraded transmission cooler. If you tow heavy and live somewhere hot, a larger bar-and-plate cooler is the next step. It only helps once the bypass valve is out of the way.
• A gauge you can trust. The factory cluster reading is fine, but a dedicated monitor such as the Edge Insight CTS3 lets you watch transmission temp, line pressure and torque converter lockup in real time, which is how you confirm the fix worked.
• Line pressure and converter upgrades. For trucks with more power or heavier trailers, the BD PressureLoc and a billet converter address the other big source of 68RFE heat, which is clutch slip under load.

Browse everything we carry in the 2019-2024 Ram 2500/3500 6.7L Cummins transmission upgrades collection.

Frequently asked questions

Questions about fitment or which valve is right for your truck? Call us or use the chat on any product page. We sell these every week and can tell you exactly what you need.