6.6L Duramax LB7 Maintenance Schedule & Service Guide | 2001 - 2004 Duramax Diesel

Applicable Models:

2001 - 2004 Chevrolet Silverado 2500/3500
2001 - 2004 GMC Sierra 2500/3500

Applicable Engine(s):

6.6L Duramax diesel LB7
(8th digit of VIN "1", see Duramax VIN ID for additional information)

Applicable Transmission(s):

Allison 1000 five speed automatic, ZF S6-650 six speed manual

Missing the owners manual from your 2001 to 2004 Chevy Silverado or GMC Sierra? Misplaced your LB7 Duramax diesel supplement? Or maybe you're in need or more comprehensive service information for your 6.6L Duramax. In any event, we've got you covered.

6.6L Duramax LB7 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).

Description Service Interval(s) Notes/Remarks
Replace engine oil & oil filter 10,000 miles/12 months or when "change engine oil" message is displayed by the oil life monitoring system [1]
Replace fuel filter, drain water separator 15,000 miles ---
Replace engine air filter 45,000 miles [2]
Perform engine cooling system service 150,000 miles [3]
Replace automatic transmission fluid & filters 50,000 miles under normal conditions
25,000 miles under severe duty conditions
[4]
Replace manual transmission fluid 60,000 miles [5]
Replace transfer case fluid 50,000 miles [6]
Replace front differential fluid 50,000 miles [6], [7]
Replace rear differential fluid
Perform multi-point inspection At oil change intervals [8]

[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 LB7 Service Parts List

Part Description Part Number(s)
Engine air filter ACDelco A1618C
Engine oil filter ACDelco PF2232
Oil pan drain plug GM 11569943
Oil fill cap ACDelco 12C45
Fuel filter ACDelco TP3018
Serpentine belt 2001 w/ 105 amp alternator ACDelco 6K1114, Gates K061114
2001 w/ 130 amp alternator ACDelco 6K1123, Gates K061123
2002 - 2004 w/ single alternator ACDelco 6K1195, Gates K061195
Thermostat Front ACDelco 131-163
Rear ACDelco 12T99D
Thermostat housing gasket ACDelco 97223686
Coolant reservoir cap ACDelco RC85
Upper radiator hose ACDelco 24485L, Gates 22698
Lower radiator hose ACDelco 26397X, Gates 22650
Glow plug ACDelco 62G (not compatible with LLY, verify VIN on 2004 MY [1])
Automatic transmission filter, auxiliary (external) ACDelco TF950, Allison 29539579
Automatic transmission filter, internal GM 29537965
Transmission pan gasket ACDelco 29549684
Front differential gasket N/A
Rear differential gasket 14 bolt, AAM 9.5 GM 26063649
14 bolt, GM 10.5 GM 26067159
14 bolt, AAM 11.5 GM 12471447

[1] For 2004 model year vehicles, verify engine is an LB7; listed glow plugs are not compatible with the 2004.5+ LLY engine. The 8th digit of the VIN number is a "1" for Duramax LB7 diesels. The 8th digit of the VIN number is a "2" for Duramax LLY equipped vehicles. Glow plugs are NOT cross compatible between LB7 and LLY engine generations.

6.6L Duramax LB7 Oil & Fluid Specs, Capacities

Item Oil/Fluid Specification Capacity [1]
Engine oil [2] Ambient temp > 0° F SAE 15W-40 API CI-4 or CH-4
Recommend Amsoil HD 15W-40 synthetic diesel oil
10 quarts w/ filter change
Ambient temp < 0° F
(acceptable in all temps)
SAE 5W-40 API CI-4 or CH-4
Recommend Amsoil HD 5W-40 synthetic diesel oil
100° F > ambient temp > 0° F SAE 10W-30 API CI-4 or CH-4
Engine coolant 50/50 solution DEX-COOL engine coolant concentrate and distilled water
(GM DEX-COOL 12346290)
~ 5.5 gallons
Automatic transmission fluid GM DEXRON VI automatic transmission fluid [3]
(ACDelco 10-9243)
7.4 quarts service refill
12.7 quarts total capacity
Manual transmission fluid GM TranSynd synthetic transmission fluid
(GM 12378515)
Recommend Amsoil Torque-Drive synthetic transmission fluid
5.8 quarts
Transfer case fluid Manual shift models GM DEXRON VI automatic transmission fluid
(ACDelco 10-9243)
Recommend Amsoil Signature Series synthetic ATF
2.0 quarts
Electronic shift models GM AUTO-TRAK II ATF
(GM 12378508, ACDelco 10-4017)
Recommend Amsoil Signature Series synthetic ATF
Front differential fluid SAE 80W-90 synthetic gear oil
Recommend Amsoil Severe Gear 80W-90 synthetic gear oil
1.8 quarts
Rear differential fluid 14 bolt AAM 9.50 SAE 75W-90 synthetic gear oil
Recommend Amsoil Severe Gear 75W-90 synthetic gear oil
2.7 - 2.8 quarts
14 bolt GM 10.5 3.2 - 3.5 quarts
14 bolt AAM 11.5 4.4 - 5.0 quarts

[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.