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).


Service Interval(s)


Replace engine oil & oil filter

10,000 miles/12 months or when "change engine oil" message is displayed by the oil life monitoring system


Replace fuel filter, drain water separator

15,000 miles


Replace engine air filter

45,000 miles


Perform engine cooling system service

150,000 miles


Replace automatic transmission fluid & filters

50,000 miles under normal conditions
25,000 miles under severe duty conditions


Replace manual transmission fluid

60,000 miles


Replace transfer case fluid

50,000 miles


Replace front differential fluid

50,000 miles

[6], [7]

Replace rear differential fluid

Perform multi-point inspection

At oil change intervals


[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



ACDelco 131-163


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


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


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 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.