The Mishimoto transmission cooler for the 2003-2005 Chevrolet/GMC 6.6L Duramax LB7/LLY is a direct-fit, stacked-plate upgrade that lowers fluid temperatures for towing, fleet, and daily-driven trucks running the Allison 1000 transmission. Its 13-row core delivers 174% greater core volume and 192% greater fin surface area than the stock cooler, and CNC-machined adapters connect to the factory lines (or AN lines) for leak-free flow with direct-fit brackets and tailor-made hoses. Note: this cooler fits late-2003 trucks with purple line clips; early-2003 orange-clip trucks use the 2001-2003 cooler.
| Brand | Mishimoto |
| Type | Direct-fit transmission cooler |
| Core | 13-row stacked-plate |
| Transmission | Allison 1000 |
| vs. Stock | +174% core volume, +192% fin area |
| Fittings | CNC-machined adapters (stock line or AN) |
| Note | Late-2003 purple-clip trucks only |
| Warranty | Mishimoto Lifetime Warranty |
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 |
