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.
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.
This Part Fits:
Year
Make
Model
Submodel
2021-2026
Chevrolet
Silverado 2500 HD
Custom
2020-2026
Chevrolet
Silverado 2500 HD
High Country
2020-2026
Chevrolet
Silverado 2500 HD
LT
2020-2026
Chevrolet
Silverado 2500 HD
LTZ
2020-2026
Chevrolet
Silverado 2500 HD
WT
2024-2026
Chevrolet
Silverado 2500 HD
ZR2
2020-2026
Chevrolet
Silverado 3500 HD
High Country
2020-2026
Chevrolet
Silverado 3500 HD
LT
2020-2026
Chevrolet
Silverado 3500 HD
LTZ
2020-2026
Chevrolet
Silverado 3500 HD
WT
2020-2026
GMC
Sierra 2500 HD
AT4
2024-2026
GMC
Sierra 2500 HD
AT4X
2020-2021
GMC
Sierra 2500 HD
Base
2020-2026
GMC
Sierra 2500 HD
Denali
2024-2026
GMC
Sierra 2500 HD
Denali Ultimate
2022-2026
GMC
Sierra 2500 HD
Pro
2020-2026
GMC
Sierra 2500 HD
SLE
2020-2026
GMC
Sierra 2500 HD
SLT
2020-2026
GMC
Sierra 3500 HD
AT4
2020-2021
GMC
Sierra 3500 HD
Base
2020-2026
GMC
Sierra 3500 HD
Denali
2024-2026
GMC
Sierra 3500 HD
Denali Ultimate
2022-2026
GMC
Sierra 3500 HD
Pro
2020-2026
GMC
Sierra 3500 HD
SLE
2020-2026
GMC
Sierra 3500 HD
SLT
Any questions?
Address frequently asked questions about this product to minimize any concerns or uncertainties that might deter a customer from making a purchase.
Does it come with a warranty?
Any products listed will have a warranty provided by the manufacturer only. Stealth Diesel is not liable for any warranty. We can assist in warranty claims but we do not provide warranty on items we dont manufacturer. Most products have a 1 year warranty. For more information on warranty, reach out to us or the manufacturer for specific warranty details.
What happens if I have an issue?
We recommend reaching out directly to the manufacturer, but we are availble to assist with any issues or concerns for troubleshooting.
How fast is shipping?
Free ground shipping will be UPS ground, typically 5-7 business days or sooner. Expidited shipping is available on in stock products only.
What's the returns policy?
Most items are returnable unopened within 30 days of purchase. A stocking fee of 20% will be deducted for all returns. Items that are non-refundable are special order, custom made, powder coated, electrical or oversize items. Return shipping is at the expense of the buyer.
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