10L80 Transmission Cooler, new and ready to install. Fits the 10L80. Ships fast from the USA.
This listing is filed as a 10L80 transmission cooler, but what ships is a new aftermarket aluminum cooler bypass kit, often called a barbell, that takes the place of the GM thermal bypass valve in the cooler line circuit. It is listed against GM valve numbers 86774933 and 85628205 and includes a fresh ACDelco cooler seal. It is not a radiator or a heat exchanger. Owners buy it when a Tahoe, Yukon, Silverado or Sierra runs hotter than it should while towing, or when the factory bypass valve is suspected of sticking and starving the cooler.
GM routes transmission fluid through a thermal bypass valve on its way to the cooler. While the fluid is cold, the valve sends it straight back to the transmission so it warms up quickly. Once the fluid reaches the valve's opening temperature, flow is sent through the cooler. GM bulletin 22-NA-182 lists those temperatures: 158 F for the 6L80 and 6L90, and 194 F for the 8L90, both with the valve outside the transmission. A barbell kit replaces that valve with a fixed passage, so fluid goes to the cooler all the time, from cold start on. The trade-off is a slower warm-up in cold weather, in exchange for lower peak fluid temperature on long pulls and no risk of a valve that sticks shut.
This is the part most listings skip. The same GM bulletin says that on the 2021 and later 10-speeds it covers, the bypass valve sits inside the valve body and opens at 143 F, so there is no external valve for this kit to replace. The exception GM names is the 3.0L Duramax (LM2 and LZ0), where the valve is on the frame rail and opens at 194 F. GM's parts catalog also lists the bypass valve 85585333, which supersedes 86774933, for 2015-2020 Tahoe, Suburban, Yukon and Escalade with the 5.3L and 6.2L, and that range takes in the early 6.2L SUVs that got the 10L80. Bottom line: if you cannot find an external valve in your cooler lines, this kit does not apply to your truck.
Rule out the cheap causes first. GM ties harsh shifts, shudder and high fluid temperature on young trucks to a cooler line that left the factory twisted, and that fix is just untwisting or replacing the line; our 10L80 cooler line guide walks through the check. Confirm the fluid level hot and the cooler fins clean. Then, with the truck at operating temperature, compare the line going into the cooler with the one coming out: if neither is warm while the transmission is hot, the valve is suspect. If the truck also flares or sets codes, read 10L80 valve body symptoms before you blame heat alone.
The kit is listed for GM 6L80, 8L90 and 10L80 applications that use the external bypass valve, 2014 and later. Fitment varies by year and by line retainer: forum reports and aftermarket fitment notes split trucks with quick-connect, clip-style line fittings from those with plate and bolt-style retainers, and a valve for one does not fit the other. Pull your existing valve, match its shape, port spacing and retainer style to the product photos, or send us your year and VIN and we will check before it ships. See the rest of our 10L80 and 10L90 parts.
| Fits | 10L80 |
| 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.
No. It is an aluminum cooler bypass kit that replaces the GM thermal bypass valve in the cooler lines so fluid flows through the cooler at all times. It works with the cooler the truck already has.
Only if your truck has an external bypass valve. GM says the 2021 and later gas 10-speeds have the valve inside the valve body, so there is nothing external to replace. The 3.0L Duramax has its valve on the frame rail. Look along your cooler lines, or send us your VIN.
The factory valve keeps fluid out of the cooler until it reaches its opening temperature, which GM lists at 158 F on the 6L80 and 194 F on the 8L90. A bypass kit sends fluid to the cooler from cold start, which lowers peak temperature under heavy load and removes a valve that can stick.
The transmission warms up more slowly in cold weather, because fluid goes through the cooler before it is hot. Most owners who tow accept that trade for lower temperatures on long pulls.
DEXRON ULV for the 10L80. On the 6L80 and 8L90, use the DEXRON grade GM lists for your truck in the owner manual. Top up after the lines are reconnected and check the level hot with the engine running.
