Alliant Power AP55203 is a remanufactured high pressure fuel injection pump for the GM 6.6L Duramax LLY. Alliant Power lists it for 2004 to 2005 Chevrolet Silverado 2500 HD and 3500 and GMC Sierra 2500 HD and 3500 trucks, and Bosch and Alliant Power date the LLY from the 2004.5 model year. Alliant Power does not list it for 2006 or later trucks.
Alliant Power lists Bosch 0 445 020 030 (new) and 0 986 437 308 (remanufactured) as substitutes, and Bosch lists those pumps under GM 97303762 and 97780091. Early 2004 trucks have the LB7, which takes a different pump (Bosch 0 986 437 303). On a 2004 truck, the engine code in the VIN tells them apart: 1 is the LB7 and 2 is the LLY.
Confirm Fitment Before You Order
Call 530-668-0818 with your VIN or engine serial number and we will confirm it is the right part before anything ships.
Specifications
| Part number | AP55203 |
|---|---|
| Brand | Alliant Power |
| Condition | Remanufactured |
| Engine | GM 6.6L Duramax LLY |
| Model years | 2004.5 to 2005 |
| Core charge | Refundable in full when we receive your rebuildable core |
| Shipping weight | 17 lb |
Fits / Applications
- GM 6.6L Duramax LLY engine, 2004.5 to 2005
- Chevrolet Silverado 2500 HD, 2004.5 to 2005
- Chevrolet Silverado 3500, 2004.5 to 2005
- GMC Sierra 2500 HD, 2004.5 to 2005
- GMC Sierra 3500, 2004.5 to 2005
Part Numbers & Cross Reference
Bosch (new) 0 445 020 030 · Bosch (remanufactured) 0 986 437 308 · GM 97303762 · GM 97780091
Frequently Asked Questions
Which trucks does AP55203 fit?
Alliant Power lists it for 2004 to 2005 Chevrolet Silverado 2500 HD and 3500 and GMC Sierra 2500 HD and 3500 trucks with the 6.6L Duramax LLY, which Bosch and Alliant Power date from the 2004.5 model year.
What numbers cross to AP55203?
Alliant Power lists Bosch 0 445 020 030 (new) and 0 986 437 308 (remanufactured) as substitutes. Bosch lists those pumps under GM 97303762 and 97780091.
Does AP55203 fit an LB7, LBZ or LMM Duramax?
No. Bosch and Alliant Power list different pumps for those engines: Bosch 0 986 437 303 for the LB7 and Bosch 0 986 437 332 for the LBZ and LMM. On a 2004 truck, VIN engine code 1 is the LB7 and 2 is the LLY.
Ships by UPS to all 50 states, including Alaska and Hawaii. Your rate shows at checkout. A refundable core charge is added at checkout.



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