10L80 Transmission Cooler 2019

Although this listing is filed under transmission coolers, the part that ships is a PPE heavy-duty deep transmission pan, raw cast aluminum, part number 128051100, for the 10L80 behind the 3.0L Duramax in the Chevrolet Silverado 1500 and GMC Sierra 1500. It is not a radiator-style cooler. It does attack the same problem from the other end: instead of pulling heat out at the front of the truck, it adds fluid and fin area at the bottom of the transmission. Diesel half-ton owners who tow, or who want a drain plug they can use at every service, are the usual buyers.

How a deep pan cools a 10L80

The pan is the sump the filter pulls from. The factory 10L80 pan has no drain plug. PPE's casting holds about 4 more quarts, and a larger mass of fluid takes longer to reach a given temperature under the same load. Internal heat-sink ribs double as baffles so fluid does not slosh away from the filter pickup, and external fins give passing air more surface to work on. A billet stainless drain plug with a neodymium magnet catches steel wear, and a tapped and plugged 1/8 in NPT port is there for a temperature sender if you want a sump reading.

This matters more on the 3.0L. GM bulletin 22-NA-182 shows the diesel's thermal bypass valve on the frame rail opening at 194 F, against 143 F for the gas 10-speeds, so the 3.0L transmission runs hot before the front cooler ever sees fluid. Extra sump volume gives you margin during that warm-up window and on long pulls.

Signs your 3.0L could use more fluid capacity

• Transmission temperature creeping up while towing, even though the shifts are normal
• Shifts that turn firm or flare only after a long hot run
• Fluid darkening early on a truck that pulls a trailer often
• A stock pan that is dented, gouged or weeping at the flange
• You are dropping the pan anyway for a filter or valve body job and want a drain plug from now on

Check these before you buy

A pan helps a hot transmission, not a broken one. Look at the cooler lines for a twist or kink first; GM ties a twisted line to high fluid temperature and harsh shifts on young 10-speeds, and the 10L80 cooler line guide covers the check. If the truck shows P0747, slams into a low gear or flares between shifts, start with 10L80 valve body symptoms. Erratic line pressure with solenoid codes is covered in 10L80 pressure control solenoid symptoms.

Fitment

The source listing reads 2019 and up for 3.0L Duramax Silverado and Sierra 1500 trucks with the 10L80. PPE dealers list 128051100 for 2020-up 3.0L trucks, which lines up with when the 3.0L diesel went into production for the 2020 model year, so treat 2020 as the practical start. It is a diesel-truck part. The 5.3L and 6.2L gas trucks, the Tahoe, Suburban, Yukon and Escalade, and the 10L90 use other pans. Check that your glovebox label shows the 3.0L engine code, or send us your year and VIN. Browse the rest of the 10L80 and 10L90 parts.

Install notes

• Drop the factory pan with the fluid warm, not hot, and let the case drain fully.
• Scrape the case flange clean and dry. The PPE pan reuses the factory-style gasket and filter, which are not in the box; the 10L80 filter and pan gasket kit covers both, and the 3.0L Duramax 10L80 service kit adds fluid.
• Snug the bolts in a crisscross pattern to factory torque. Overtightening a cast pan on a rubber gasket only distorts the seal.
• Fill with DEXRON ULV. GM's service fill is 8.1 qt; with the deep pan, expect to add roughly 4 qt beyond what drained.
• Set the level hot with the engine running, then check the drain plug and the NPT plug for seepage after a test drive.

Is this an external transmission cooler?

No. It is a PPE 128051100 deep cast aluminum transmission pan. It lowers fluid temperature by adding about 4 quarts of capacity and cooling fins, not by adding a heat exchanger.

Which trucks does it fit?

Silverado 1500 and Sierra 1500 with the 3.0L Duramax and the 10L80. PPE dealers list 2020 and later. It does not fit the gas trucks or the full-size SUVs.

Do I need a new filter and gasket?

Yes. The pan works with the factory-style gasket and filter, and neither is included. Replace both when you install it.

How much fluid should I buy?

GM lists an 8.1 qt service fill for the 10L80. Add about 4 qt for the deep pan, and use DEXRON ULV only.

Can I add a temperature sensor?

Yes. The pan has a tapped and plugged 1/8 in NPT port for an optional fluid temperature sender.

• 10L80 Cooler Line Replacement Guide
• 10L80 Valve Body Symptoms and Testing
• 10L80 Pressure Control (EPC) Solenoid Symptoms
• GM 10L80 Transmission Problems: The Valve Body Wear Behind the Wheel-Lock-Up Recall