6.6L Duramax LLY Maintenance Schedule & Service Guide | 2004 - 2006 Duramax Diesel

6.6L Duramax LLY Maintenance Schedule (Service Intervals)

"Severe duty" service conditions may include any of the following:

• Light towing that exceeds 1,000 miles during any applicable service interval.
• Medium to heavy towing or hauling payloads that place the vehicle near its maximum GVWR.
• Extended periods of idling, generally accepted as 10 minutes of idling or more during a 60 minute window.
• Driving off-road or in dusty conditions.
• Frequent driving in heavy stop-and-go traffic conditions.
• Driving in a manner that prevents the engine from reaching normal operating temperature (frequent stops and/or short trips).

^[1] Do not exceed 10,000 miles between oil changes. More frequent oil changes may be advisable if towing frequently, hauling payloads near GVWR, or idling for extended periods of time. Recommend changing engine oil every 12 months if mileage does not meet service criteria.
^[2] Check air filter condition at oil change intervals and replace as necessary. Driving in dusty conditions will require more frequent air filter replacements.
^[3] At minimal, drain coolant from engine cooling system and replace thermostats, upper radiator hose, lower radiator hose, and replenish with new coolant/distilled water solution. Inspect remaining hoses and overflow tank, replace as necessary. Recommend that subsequent cooling system services are performed at 50,000 mile intervals after the initial 150,000 mile service.
^[4] Replace external and internal transmission filters, replenish with new automatic transmission fluid.
^[5] GM does not necessitate changing the manual transmission fluid; Diesel Hub recommendation provided. Shift quality will be maintained and transmission life prolonged if serviced regularly.
^[6] Replace transfer case and differential fluid immediately anytime these components are submerged in water; water infiltration is highly likely.
^[7] No service interval provided by GM; recommend replacing front and rear differential gear oil at 50,000 mile intervals to prolong life.
^[8] Multi-point inspection should include examination of ball joints, universal joints, CV joints, air filter, fuel system (leak detection), exhaust system, and vehicle brake condition. Grease applicable Zerk fittings as required.

6.6L Duramax LLY Service Parts List

6.6L Duramax LLY Oil & Fluid Specs, Capacities

^[1] Oil and fluid capacities are nominal; always fill to proper fluid indicator level (i.e. dipstick), fill plug height, or applicable level identifier. Vehicle should be parked on a level surface when checking or adjusting fluid level.
^[2] 15W-40 engine oil preferred in ambient temperatures above 0° F. 5W-40 is acceptable in all ambient temperatures, but only preferred (and required) when ambient temperatures are below 0° F. 10W-30 engine oil is acceptable within listed temperature range, but not preferred under any conditions.
^[3] DEXRON VI ATF supersedes previous DEXRON III specification; all applications requiring DEXRON III transmission fluid should use the newer DEXRON VI ATF.