6.6L Duramax LYE & LRX

Duramax LYE, LRX Engine Specs & Information

The Duramax LYE and LRX engines are commercial versions of the Duramax LMM. These derated engine options were only available in GM's medium duty trucks, the GMC TopKick and Chevrolet Kodiak. The LYE and LRX order codes were used during the 2007 and 2010 model years for these applications. Like the LMM, the LYE and LRX were retired following the 2010 model year in favor of the next generation Duramax.

The order codes for the LYE and LRX defined different power ratings available in the Chevrolet Kodiak and GMC TopKick. The LYE option specified a 330 horsepower, 620 lb-ft Duramax diesel while the LRX option specified a 300 horsepower, 520 lb-ft variation of the Duramax diesel. It is largely common for commercial vehicles to feature an alternative engine configuration than that found in pickup models and the practice is implemented industry wide. The LYE and LRX also feature a marginally lower 3,250 rpm max engine speed compared to the standard LMM's 3,450 rpm redline. For a more detailed spec sheet, see: 6.6L Duramax LMM Engine Specs

6.6L Duramax LYE, LRX Specs


6.6L Duramax LYE/LRX, 90 degree V8 diesel


2007.5 - 2010 Chevrolet Kodiak, GMC TopKick medium duty trucks

Assembly Site:

DMAX engine plant, Moraine, Ohio


403 cubic inches, 6.6 liters

Head/Block Material:

Aluminum cylinder heads, cast iron engine block


4.055" (103 mm)


3.897" (99 mm)


Turbocharged and intercooled; variable vane turbocharger (VVT), air-to-air intercooler


26,000 psi Bosch high pressure common rail with CP3 injection pump


OHV (overhead valve), 4 valves per cylinder

Oil Capacity:

10 quarts with filter

Max Engine Speed:

3,250 rpm

Peak Horsepower:


330 hp @ 3,000 rpm


300 hp @ 3,000 rpm

Peak Torque:


620 lb-ft @ 1,600 rpm


520 lb-ft @ 1,600 rpm

Duramax LYE, LRX Horsepower & Torque Curve

6.6L Duramax LYE, LRX horsepower and torque curve

6.6L Duramax LYE horsepower and torque curves as advertised for Chevrolet TopKick medium duty applications.
Maximum horsepower rated at 330 hp @ 3,000 rpm and peak torque rated at 620 lb-ft @ 1,600 rpm.