GM CHEVROLET 6.6L LMM ENGINE

The GM CHEVROLET 6.6L LMM ENGINE (403 ci) V8 turbo-diesel belonging to GM’s Duramax engine family, produced between 2007.5 and 2010 .

• It delivers up to 365 hp at 3,200 rpm and 660 lb‑ft of torque at 1,600 rpm in Silverado/Sierra applications .

• The engine features: cast gray‑iron block, aluminum heads, Bosch CP3 injection, Garrett variable‑geometry turbocharger, DPF, DOC, and EGR for emissions control, and weighs approximately 835 lb

• The RPO code is GM CHEVROLET 6.6L LMM ENGINE, and it’s identified by the 8th digit “6” in the VIN .

• It was used in heavy‑duty trucks, including the Silverado/Sierra 2500/3500 HD, Express/Savana vans, and medium-duty Kodiak/TopKick trucks

Reliability & Owner Insight Of GM CHEVROLET 6.6L LMM ENGINE

• Duramax LMMs are known for long service life. One owner reported over 700,000 km (approx. 435,000 mi) with no major issues.

• Another noted solid decades of basement durability:

• Common preventive advice includes checking for fuel rail pressure issues, assessing CP3 pump and injectors, and avoiding tuner modifications Practical upgrades suggested include transmission cooler lines and a Fass lift pump to protect the CP3 pump

Purchasing Options — New, Remanufactured, Pre‑Owned

A) Pre‑Owned GM CHEVROLET 6.6L LMM ENGINE

• Listings on Google show used GM CHEVROLET 6.6L LMM ENGINE (with VIN 6) for around US $4,249 to $4,949, often with a 90‑day warranty and free shipping .

• Another listing for a reman long block engine is priced at US $9,595, includes a core charge, with several units available and 30‑day returns

B) Remanufactured / Crate Engines Of GM CHEVROLET 6.6L LMM ENGINE

• Choate Reman Long Block: Approximately US $6,800, with precision CNC machining, new internals such as pistons, rings, bearings, and remanufactured heads .

• Choate Daily Driver Long Block: Around US $12,700, includes even more new components and a 5‑year / 100k‑mile warranty .

• Choate Workhorse Long Block: Priced at US $15,000; includes upgraded Stage 2 camshaft, chromoly pushrods, coated pistons, and more .

• DFC Diesel KORE Series Long‑Block: Includes upgraded Callies crankshaft, professional machining, gasket improvements, gaskets, and silicone; warranty varies (1 year/unlimited mileage)

• DFC Diesel Reman Long Block: Similar to above but with extended 5‑year / 100k‑mile warranty

• DFC Street Series (for Kodiak/Topkick): Doesn’t include oil pan or rear housing; warranty 5‑year / 100k miles

Summary of Options with Pricing & Features

Where to Buy: Best Places to Find the GM CHEVROLET 6.6L LMM ENGINE

Here are some reputable sources for buying new, used, or remanufactured GM CHEVROLET 6.6L LMM ENGINE:

 BUD’S AUTO PARTS

Great for used OEM pull-outs

• Examples: Engines with ~180k miles, VIN verified, $4,200–$4,900

• Buyer protection and return windows included

 XtremeDiesel.com

• Offers high-end crate engines from Choate, DFC, and Industrial Injection

• Full reman and custom builds with 1–5 year warranties

• Price range: $6,800 – $15,000

 HoldersDiesel.com

• Home of Choate Engineering Performance Engines

• Great for upgraded “Daily Driver” or “Workhorse” long blocks

• Premium internals, coatings, and tuning potential

 InjectedMotorsports.com

• Specializes in performance builds for street and off-road

• Offers both long blocks and short blocks tailored for racing, towing, or heavy hauling

 Facebook Marketplace / Craigslist

• Often find complete part-outs, project truck swaps, or running trucks

• Riskier—verify VIN and compression tests before purchasing

GM CHEVROLET 6.6L LMM ENGINE in Heavy-Duty & Commercial Applications

While many associate the GM CHEVROLET 6.6L LMM ENGINE with pickup trucks, it also powered:

• Chevrolet Kodiak / GMC TopKick 4500–6500 class trucks

• Chevy Express / GMC Savana 2500/3500 Vans

Its reputation in commercial fleets is well established. Many municipalities and delivery companies reported 250,000+ miles with basic maintenance.

Key Strengths in Commercial Use:

• Strong torque for towing and hauling (660 lb-ft)

• Excellent longevity with minimal mods

• Compatible with PTO systems in utility and work trucks

• Emissions-compliant for most U.S. jurisdictions (when stock)

 Tips for Long-Term Ownership

If you’re buying or rebuilding an GM CHEVROLET 6.6L LMM ENGINE, follow these expert-backed tips for maximum life and value:

 Maintenance Schedule:

• Oil changes: Every 5,000 miles with 15W‑40 (or 5W‑40 synthetic)

• Fuel filter: Every 15,000 miles

• Transmission service: Every 50,000 miles

• Coolant flush: Every 100,000 miles

 Preventive Upgrades:

• FASS or AirDog fuel system to protect CP3

• Upgraded transmission cooler lines to prevent blowout

• Downpipe-back exhaust to improve flow (DPF-compatible or off-road delete)

• EGR blocker (off-road) or upgraded EGR cooler to reduce clogging

• Head studs for built setups (above 550+ hp)

 Common Issues to Monitor:

• Injector balance rates (scan with Tech2 or Autocal)

• DPF regen frequency (if still installed)

• CP3 pump wear signs (low rail pressure, hard starts)

• Glow plug module faults in cold climates

 Is the GM CHEVROLET 6.6L LMM ENGINE Right for You?

Choose the GM CHEVROLET 6.6L LMM ENGINE if you want:

• A modern Duramax with emissions compliance

• Strong tuning potential with no CP4 failure risk

• Affordable used engines still on the market

• Compatibility with Allison 1000 6-speed (a robust transmission)

However, if you’re emissions-averse or want a cleaner slate for builds, earlier LBZ or newer L5P may offer better stock performance or fewer emissions components.

Final Words

The GM CHEVROLET 6.6L LMM ENGINE is a powerhouse — whether you’re replacing a worn-out powerplant, restoring a Silverado HD, or building a custom tow rig. Its blend of power, durability, and availability makes it one of the most popular used diesel engines on the market.

With used engines available for around $4,000–5,000, and performance crate builds ranging $6,800–15,000, there’s an option for every budget. Whether stock or modified, the LMM offers outstanding long-term value — especially if maintained properly and upgraded wisely.