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MMTC-DMAX-03SL Mishimoto Heavy Duty Transmission Cooler - GM 2003.5-2005 (WITH PURPLE CLIPS)

Manufacturer: Mishimoto
Mishimoto's new transmission cooler for your 2003.5-2005 GMC/Duramax LB7/LLY has 174% greater core volume and 192% greater external fin surface area over the stock OEM cooler. If you tow, then this cooler is a must!

PRODUCT DETAILS (click to expand)

Mftr. Part# MMTC-DMAX-03SL
UPC 811580034084
Weight (lbs.): 14.00 lbs.
Dimensions: 4.00" x 29.00" x 11.00"

PRODUCT SPECS (click to expand)

Product Type Transmission Cooler
Transmission Type Allison A1000
$588.00 (CAD)


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 its durable construction, this transmission cooler is significantly larger than the stock core. The Mishimoto transmission cooler boasts a 174% greater core volume, and 192% 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.


  • Direct fit for all 2003.5–2005 Chevrolet/GMC 6.6L Duramax (LB7/LLY)
  • Stacked-plate construction for maximum durability and superior cooling
  • CNC-machined adapters make it easy to connect Mishimoto cooler to stock fluid lines or AN lines
  • 174% greater core volume than stock cooler
  • 192% greater external fin surface area over stock cooler
  • Mishimoto Lifetime Warranty

*Fits 2003 trucks with purple clips. This kit will not fit early 2003 trucks that have orange clips. Verity before ordering.

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