Mishimoto 2020+ Chevrolet / GMC Duramax L5P 6.6L Transmission Cooler
Can I pick up my order or have it installed at your shop?
Can I pick up my order or have it installed at your shop?
Absolutely. We offer local pickup on most products and full professional installation at our shop in Washington, MO. Whether you just want to grab your parts or have our techs handle the install, we’ve got you covered. Give us a quick call at 636-429-7020 or message us to schedule a visit — we’ll make sure the parts are ready when you arrive.
How do I know if this part fits my vehicle?
How do I know if this part fits my vehicle?
Unsure if it’ll fit? No problem — that’s what we’re here for. Send us your vehicle’s year, make, and model, and we’ll verify fitment before you order. We can also point you toward compatible upgrades or supporting parts if needed.
What if I need to return a product or it’s defective?
What if I need to return a product or it’s defective?
Most unused items can be returned within 30 days in their original packaging. Some products are covered by a manufacturer’s warranty as well. If something arrives damaged or doesn’t meet your expectations, just let us know — we’ll help you get it replaced, refunded, or repaired. (Tracking updates are also emailed automatically once your order ships.)
What's the lead time on custom or fabricated parts?
What's the lead time on custom or fabricated parts?
Many of our parts are built to order — especially fabricated or performance components. These can take additional time to produce before shipping. Lead times vary by manufacturer and demand, but we’ll always keep you updated along the way. If you’re working on a tight schedule, reach out before ordering at 636-429-7020 and we’ll confirm current availability or estimated ship dates.
Description
Description
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 |









