Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 7 - Jul 12
Promo Codes Available:
For Your Every Summer RSVP, with Code: SUMMER15
Description
Mishimoto 03-05 Chevrolet / GMC 6.6L Duramax (LB7/LLY) Transmission CoolerThere's no greater enemy for a transmission than heat. Whether your 2003 2005 Chevy GMC 6. 6L Duramax is a dedicated tow vehicle, hardworking fleet truck, or a daily driver with a liking for the drag strip, you need to ensure that your transmission runs cool. Luckily, Mishimoto has developed a direct fit transmission cooler to do just that. Our 2003 2005 Chevy GMC 6. 6L Duramax transmission cooler utilizes a stacked plate design for maximum durability
There's no greater enemy for a transmission than heat. Whether your 2003-2005 Chevy/GMC 6.6L Duramax is a dedicated tow vehicle, hardworking fleet truck, or a daily driver with a liking for the drag-strip, you need to ensure that your transmission runs cool. Luckily, Mishimoto has developed a direct-fit transmission cooler to do just that. Our 2003-2005 Chevy/GMC 6.6L Duramax transmission cooler utilizes a stacked-plate design for maximum durability and powerful cooling. Aside from It's durable construction, this transmission cooler is significantly larger than the stock core. The Mishimoto transmission cooler boasts a 174-percent greater core volume, and 192-percent greater fin surface area than the stock 2003-2005 Duramax transmission cooler. The included CNC-machined adapters connect directly to the stock transmission cooler lines for leak-free cooling. Direct-fit brackets and tailor-made hoses make installation easy. Like all Mishimoto products, this transmission cooler is backed up by our Lifetime Warranty with Accident Protection for worry free cooling as long as you own it.This Part Fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2003-2005 | Chevrolet | Silverado 2500 HD | Base |
| 2003-2005 | Chevrolet | Silverado 2500 HD | LS |
| 2003-2005 | Chevrolet | Silverado 2500 HD | LT |
| 2003-2005 | Chevrolet | Silverado 2500 HD | WT |
| 2003-2005 | Chevrolet | Silverado 3500 | Base |
| 2003-2005 | Chevrolet | Silverado 3500 | LS |
| 2003-2005 | Chevrolet | Silverado 3500 | LT |
| 2004 | Chevrolet | Silverado 3500 | WT |
| 2003-2005 | GMC | Sierra 2500 HD | Base |
| 2003-2005 | GMC | Sierra 2500 HD | SLE |
| 2003-2005 | GMC | Sierra 2500 HD | SLT |
| 2003-2005 | GMC | Sierra 2500 HD | WT |
| 2003-2005 | GMC | Sierra 3500 | Base |
| 2003-2005 | GMC | Sierra 3500 | SLE |
| 2003-2005 | GMC | Sierra 3500 | SLT |
| 2004-2005 | GMC | Sierra 3500 | WT |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.8 ★★★★★
Based on 2375 reviews
Sort
Product Reviews
★★★★★ 5
Nice
Size: 16AWG Wiring Harness-2 Leads
Worked great, easy to install
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 8, 2026
★★★★★ 4
Wire length between the two connectors is short for a full-size pickup
Size: 16AWG Wiring Harness-2 Leads
I used the harness to wire ditch lights on opposite sides of a full-size pickup (F150). The wire between the 2 2-pin connectors was about 18 inches too short. Fortunately, splicing the wires from the (Nilight) ditch lights and the included pigtails gave barely enough length to reach the connectors. The connectors are buried inside the trim channel for the cowl; I'd have preferred they were exposed on each side to allow for easy swapping of the lights, but I can live with it. There is more than enough wire from the first connector to the relay for my all-under-hood installation, but I didn't think to measure if it would reach into the truck bed. The harness is of good quality and is a very good value. It would be a 5-star if it weren't for that little length issue.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 1, 2025
★★★★★ 5
great value
Size: 16AWG Wiring Harness-2 Leads
very affordable light install kit. worth the price just in the wiring connectors. I used this with my Nilight front bumper kit. i bypassed the button and wired high beam (+) to the yellow small wire. I did this so when the highbeams come on the light bar comes on. because with the stock arragement of this harness, the button continously draws power for the indicator LED
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 30, 2026
★★★★★ 5
The Easiest!
Size: 16AWG Wiring Harness-2 Leads
This is one of the best and easiest wiring system to install that I have every used. And the price is great!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 11, 2025
★★★★★ 5
Well done. Useful.
Size: 16AWG Wiring Harness-2 Leads
Always well done.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 24, 2025