Mishimoto 2020+ Chevrolet / GMC Duramax L5P 6.6L Transmission Cooler
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
The factory transmission cooling on the 2020+ Chevrolet and GMC Duramax L5P 6.6L is sized for stock duty, and fluid temperatures climb fast under the sustained load of towing and heavy hauling. Heat is what wears a transmission out. The Mishimoto Transmission Cooler attacks the problem with raw capacity: a tube-and-fin core with a 245% increase in core volume over stock, giving the system far more headroom to keep fluid temperatures in a safe range when the truck is working hardest.----The core also adds a 137% increase in frontal area, putting more of the cooler directly in the incoming airstream, and a 173% increase in external fin area to move heat from the fluid into the air more efficiently. All-aluminum construction handles the thermal demands of stock and modified Duramax trucks alike, and the cooler retains the factory transmission line connections for a clean, complete upgrade with no additional adapters or plumbing.----Direct fit for the 2020+ Chevrolet and GMC Duramax L5P 6.6L. No drilling, cutting, or modification required. Backed by the Mishimoto Lifetime Warranty.
Installation Instructions- 245% larger core volume for serious heat dissipation - the oversized tube-and-fin core gives the transmission far more capacity to pull heat from the fluid under tow and heavy load.
- Tube-and-fin aluminum core built for sustained load - durable all-aluminum construction holds transmission temps in check through the heat of towing where stock cooling falls short.
- 173% more external fin area accelerates heat transfer - the added fin surface moves thermal energy from the fluid into the airstream far more efficiently than the stock cooler.
- Factory connections, no adapters required - the cooler uses the OEM transmission line connections for a complete bolt-on upgrade with no extra fittings or plumbing work.
- 137% more frontal area catches more cooling airflow - the larger frontal core area puts more of the cooler in the incoming airstream to drop fluid temps faster.
- Drops in without modification - confirmed direct fit for 2020+ Chevrolet and GMC Duramax L5P 6.6L trucks, with no cutting, fabricating, or adapter work required
- Own it for life - backed by Mishimoto’s Lifetime Warranty, your investment is protected long after install day.
Shipping information
We currently ship within the United States only. Most in-stock orders ship within 1 business day, and standard delivery takes 5-10 business days depending on your location. Shipping is calculated at checkout based on destination and item weight, and a tracking number is emailed to you once your order ships.
See our FAQ for full shipping details.
Returns & warranty
Returns are accepted within 14 days of delivery on new, unused, and uninstalled items in their original packaging. A 15% restocking fee applies, and a Return Merchandise Authorization (RMA) number must be requested before shipping any return. Some items are not eligible for return, including electronics, engine internals, turbo/supercharger kits, special orders, and Sale/Clearance items.
All products are covered by the original manufacturer's warranty. For returns or warranty help, email contact@sabaku-parts.com. Full details are in our FAQ.