When the CP4.2 high-pressure pump lets go on an LML Duramax, it does not fail quietly. The pump grinds itself apart and pushes steel debris downstream through the rails, the lines and every injector. Replacing the pump alone puts a new pump into a system still full of the old one — which is why those repairs come back. This kit exists to replace the contaminated fuel system as a unit.
This is the pump-included version. Alliant Power also builds a no-pump variant (AP57004NP) for shops that are sourcing the CP4.2 separately or converting to a different pump.
| Part number | AP57004 |
| Brand | Alliant Power |
| Condition | Remanufactured — rebuilt to original specification and tested |
| Application | 2011–2016 Chevrolet Silverado and GMC Sierra 2500HD / 3500HD, 6.6L Duramax LML |
| High-pressure pump | Included in this kit |
| Shipping weight | 39 lb |
| Warranty | Alliant Power factory warranty on this unit. On anything we remanufacture in house: 1 year, 30 days on electrical components |
| Core charge | Refundable $1,000.00, refunded in full when we receive your rebuildable cores |
Fits / Applications
- 2011–2016 Chevrolet Silverado and GMC Sierra 2500HD / 3500HD, 6.6L Duramax LML
- LML platform with the Bosch CP4.2 high-pressure pump
- Correct repair path after a confirmed CP4.2 failure with metal contamination downstream
- Not for LB7 / LLY / LBZ / LMM Duramax, which use the CP3 pump — call and we will point you to the right kit
What The Kit Covers
- Remanufactured high-pressure fuel pump (included in this version — the NP variant omits it)
- Remanufactured fuel injectors for all eight cylinders
- Fuel rails and high-pressure lines from the contaminated circuit
- The supporting seals and hardware Alliant Power packages with the kit
Kits are packaged by Alliant Power and the exact component list can change by production revision. Call 530-668-0818 and we will read you the current contents for your build before you order — worth two minutes on a repair this size.
Why do I see this kit cheaper online?
Short answer: it is usually not the same part — and you are buying this because a part already failed. Read why ↓
Search any OE number and eBay, Amazon and a dozen storefronts will show it well under dealer cost, sold by outfits with no name, no address and no phone number. We lose business to those listings every week — and we see a lot of them come back through our shop. Here is what is actually different.
- The part number proves nothing on its own. Counterfeit injectors and pumps are stamped with the same OE numbers as the real thing, in housings cast to look identical. The number in the listing title tells you what the seller claims it is, not what came off an OE line.
- “Remanufactured” is not a regulated word. A genuine reman unit is stripped to bare components, has its wear parts replaced — nozzle, plunger and barrel, solenoid, seals — and is then run on a calibration bench until it meets the original flow and response spec. A cheap one is very often cleaned, resealed, painted and shipped. Both get called remanufactured.
- No full teardown, so no idea what is worn. A proper rebuild means the unit comes apart completely and every part gets inspected and measured against spec — not just the ones that are obviously bad. Skip the teardown and you are reusing worn internals inside a freshly painted housing. It will run on the truck. It will not last.
- No factory-spec bench load testing. A unit is not finished until it has been run under load on a test bench and made its numbers across the range, not just at one easy point. That bench time is most of what you are paying for. Sellers working on price cut it first, because nobody can see it in a photo.
- The warranty has to be honored by someone. Everything we remanufacture in house carries a one-year warranty, with 30 days on electrical components. Parts we supply as an authorized dealer carry the manufacturer’s own warranty. Either way you call us, a real shop in California, and we sort it out. A marketplace warranty usually means shipping the part overseas at your own cost and hoping for a reply.
- No core program. We credit your rebuildable core back in full. Discount sellers generally will not take one, so the gap narrows the moment you account for the core you are now stuck holding.
- This kit exists because of a failure like that. A contamination kit is what you buy after a high-pressure pump has already put metal through the fuel system. Fitting uncertified components into that repair — the exact repair caused by an out-of-spec part — is how trucks come back a second time.
We are an authorized dealer and a working fuel-injection shop — we have been rebuilding and testing this hardware in Woodland since 1993, and the people who answer the phone are the people who run the benches. Not sure this is the right part for your engine? Call us with your serial number before you order and we will confirm it. Send your rebuildable core back and the core charge is refunded. And if a price somewhere else looks too good, call 530-668-0818 and we will tell you straight whether it is a deal or a problem.
Why Buy From Valley Fuel Injection
We are a diesel fuel-injection and turbocharger shop in Woodland, CA — rebuilding pumps, injectors and turbos on our own benches since 1993, not a drop-ship storefront. When you call, you talk to the people who test these units. Not sure which version your engine takes? Call us with your engine serial number before you order and we will confirm it — that check is free and takes a couple of minutes.
Ready to order online and ships free ground in the lower 48 states. A refundable $1,000.00 core deposit is added at checkout and refunded in full when we receive your rebuildable cores. Questions on fitment? Call 530-668-0818.
Pricing covers the unit itself. Any applicable sales tax and the refundable core charge are additional; ground shipping in the lower 48 is free. Buying tax-exempt? Qualifying diesel repair shops, fleets, farms, and agricultural operations can purchase tax-free. Set up tax-exempt purchasing once and every qualifying order is tax-free going forward.
Pump Included Or Not?
This build includes the high-pressure pump. If you are supplying your own pump or doing a CP3 conversion, see AP57004NP — same platform, no pump, lower price.










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