06 GMC C6500,
7.8 Duramax LG4
VIN 1GDJ6C1326F4xxxxx
Odometer Reads 243,084
Allison auto
11.00 22.5 tires front, 10.00/22.5 tires rear. 243k miles.
Jerr Dan 21' Steel Bed BIC with independant wheel lift.
Muncie PTO P/N: TG6B-A6906-Z1KX
Muncie Hyd Pump PL1-27-02BPBBX
Air Filter P614876
Engine Oil P553191
Fuel/Wtr Sep P551840
Hyd P550606
PS P550309
Info storage in first post you will probably want to skip.
Vehicle Information
The 7.8L Duramax LG4 was offered in one of several tiered output ratings ranging from 195 to 300 horsepower and 441 to 860 lb-ft of torque. Note that the available ratings varied between applications and there are at least 16 different configurations, although only 11 of the combinations were available in Kodiak and TopKick applications, ranging between 200 and 300 horsepower and 520 and 860 lb-ft of torque. The 7.8L Duramax was offered alongside GM's 8.1L Vortec V-8 (RPO code L18) and the Caterpillar C7 (RPO code LG5). The Cat C7 was offered in similar power configurations with a maximum torque output of 800 lb-ft.
When the 7.8L Duramax adopted a diesel particulate filter for the 2008 model year, the RPO code was changed to "LF8" and GM began referring to the engine as the "Duramax" less and the "Isuzu 6H" designation became more common in owners manual and spec sheet references. The engine features a high pressure common rail injection system with solenoid-type fuel injectors and a Denso injection pump. A Garrett variable geometry turbocharger was employed for minimal turbocharger lag and favorable response across the operating range.
[1] - There are some discrepancies in the listed compression ratio for the 7.8L Duramax; the original GM spec sheet from 2003 lists the compression ratio at 16.0 to 1 while the 2003 Isuzu 6HK1 workshop manual lists the compression ratio as 17.5 to 1. Compression ratio may differ with horsepower ratings.
[2] - Full load governed engine speed dependent on model year and horsepower/torque configuration.
[1] - RPO code LPS denotes a 195 horsepower power option for the 7.8L Duramax, however this power rating was never advertised for Kodiak, TopKick, or T-Series cabover truck models. The 200 horsepower, 441 lb-ft variant of the engine was standard on the 2003 model year WT5500 cabover, but was never offered in the Chevrolet Kodiak nor GMC TopKick
TG-INPUT (A69)
$195.79 $335.02
SKU 03T38783
7.8 Duramax LG4
VIN 1GDJ6C1326F4xxxxx
Odometer Reads 243,084
Allison auto
11.00 22.5 tires front, 10.00/22.5 tires rear. 243k miles.
Jerr Dan 21' Steel Bed BIC with independant wheel lift.
Muncie PTO P/N: TG6B-A6906-Z1KX
Muncie Hyd Pump PL1-27-02BPBBX
Air Filter P614876
Engine Oil P553191
Fuel/Wtr Sep P551840
Hyd P550606
PS P550309
Info storage in first post you will probably want to skip.
Vehicle Information
- Productiondate2006-05-10
- CatalogCode61C
- MakeCodeM
- ModelCodeC
- Vehicle2006 Medium Truck C-Series 6500 / 7500 / 8500
- EngineENGINE, 7.8L DIESEL TURBO ISUZU 6 CYL-INLINE
- Model StringTOPKICK C6500 CONV CAB 4X2
- TransmissionTRANSMISSION AUTO 5 SPD, ALLISON, LCT 2500, 3.51 1ST, 1.00 4TH .74 5TH, O/D, CONV CLUTCH
- CATALOG61C-
- MDC-
- MKM-
- SG0495-
- YEAR_FROM2006-
- YEAR_TO2006-
- RAT009-RATIO CODE, 5.29
- CCL50L-EXTERIOR COLOR, SECONDARY, WHITE
- CCU50U-EXTERIOR COLOR , PRIMARY, OLYMPIC WHITE
- TRM69I-INTERIOR TRIM COLOR, MEDIUM BEIGE/VERY DARK PEWTERINTERIOR TRIM COLOR, VERY DARK PEWTER;69V-TRIM COMBINATION VINYL, MED BEIGETRIM COMBINATION VINYL, V/D PEWTER
- STSA58-SEAT, AUXILIARY, TWO PASSENGER;AS4-SEAT FRT BKT, HIGH BACK, DRIVER
- RESAL3-RESTRAINT SYSTEM, FRONT SEAT, INFLATABLE, DRIVER, DELETE
- PRSBPV-FIRST POSITION PROP HANGER, NON-BOC, HEIGHT B;ERC-SECOND POSITION PROP HANGER, HEIGHT C
- HTRC60-AIR CONDITIONER, FRONT, MANUAL CONTROLS
- PLTCMD-PLANT CODE FLINT, MI, GM T&B
- MIRDB5-MIRROR O/S LH & RH, WIDE LOAD, INTEGRAL ARM
- ASHDT4-ASH RECEPTACLE AND CIGARETTE LIGHTER
- MNTEJ5-BODY MOUNT, HYSTEC
- WLBEK7-WHEELBASE 260 INCH
- SATEV9-SUSPENSION, ATTACH BOLTED
- FRQFD5-FRAME RAIL, FULL DEPTH, 245 X 8, 80K
- HUBFF1-HUB, FRONT, OIL FILLED
- FAXFM8-AXLE FRONT 8, 000 LB CAPACITY
- SPFFSN-SUSPENSION FRONT 8, 000 LB, TAPERLEAF
- RSPG60-SPRING, REAR AUXILIARY
- SHKG68-SHOCK ABSORBERS, REAR, HEAVY DUTY
- SSRGN0-SPRING, REAR 8620 KG, (19, 000 LB)MULTILEAF
- GVWGZI-GVW RATING 25, 950 LBS
- SPRGZT-PROVISIONS TAPERLEAF/MULTILEAF RR SPRINGS
- RAXHPK-AXLE REAR EATON 19060S, SINGLE SPEED, 19000 LB CAP
- BRKJE3-HYDRAULIC BRAKE SYSTEM
- UJTJPE-JOINT MAIN UNIVERSAL, SPL 100 SERIES
- CCNK34-CRUISE CONTROL, AUTOMATIC, ELECTRONIC
- GENK60-GENERATOR, 100 AMPERE
- EBHKB3-HEATER ENGINE BLOCK, 115V, 1250 WATT
- ACLKNB-AIR CLEANER DRY
- ECPKPJ-ENGINE SHUTDOWN AUTOMATIC;PTO-PROVISIONS POWER TAKE OFF CONTROLS
- PWOLQB-POWER OPTION ISUZU, 7.8L, 200 GROSS HP @ 2400 RPM
- PTOM1F-POWER TAKE OFF REAR
- OILMBT-LUBRICANT FLUID-A/TRNS (TRANSYND)
- CLPMWE-PILOT SHAFT-AUTO TRANS WITH HYDRAULIC SHIFT-NO SPLINE
- EXHNB5-EXHAUST SYSTEM, SINGLE
- EMSNC8-EMISSION SYSTEM, CALIFORNIA, ULEV;YF5-CALIFORNIA EMISSION CERTIFICATION
- TNKNNQ-FUEL TANK 201L, 53 GAL, DUAL, RECT, STEEL, STEP
- FSUNWB-SEPARATOR, RACOR, SPIN-ON, FUEL/WATER WITH BOWL AND DRAIN
- AGLPNQ-PROP SHAFT ANGLE, REAR AXLE PINION, NOMINAL 3 DEGREE
- WHLPQU-WHEEL, FRONT GENERIC STL, 10 HOLE, 11.25 BC, PILOTED, DISC;PQV-REAR STEEL DISC WHEEL, 11.25 IN BC PILOTED;QH3-WHEEL FRT 22.5X7.50, 10 HOLE, 11.25 BC, FN, HUB PILOTED, (29001);QH4-WHEEL, REAR, 22.5 X 7.5, 10 HOLE, PILOTED HUB
- VEAPRS-IDENTIFICATION PRO-SPEC;RQ2-VEHICLE APPLICATION TRUCK SERVICE;VC0-VEHICLE LABEL, NOISE CONTROL INFORMATION;VXT-LABEL INCOMPLETE VEHICLE
- TTFR3C-FRONT TIRE TREAD PREMIUM HIGHWAY
- TBFR4A-FRONT TIRE BRAND GOODYEAR
- FINR8G-CONTROL-SALES ITEM NO. 57;R9M-CONTROL - SALES ITEM NO. 88
- TTRS3H-TIRE TREAD REAR HIGHWAY TRACTION
- TBVS4A-TIRE BRAND REAR GOODYEAR
- SPCSLM-SALES PROCESSING-STOCK ORDERS;YF6-GEOGRAPHIC CONTROL-CALIFORNIA
- SCRSMB-SPACER PACK, RH SPRING CAB LEVELING, +0 MM
- BATTNL-BATTERY, TWIN 12V(1110)
- I05TRG-TIRE FRONT CUSTOMER SPECIFIED BRAND
- TSRTRH-TIRE REAR CUSTOMER SPECIFIED BRAND
- HORU08-HORN, DUAL ELECTRIC
- RDOUM7-RADIO, AM/FM STEREO, ETR, CLOCK
- CERX80-PLATE GVW RATING
- FTRXWJ-TIRE FRONT 10.00R22.5/F 12PR BL RADIAL TL
- RTRYWJ-TIRE REAR 10.00R22.5/F 12PR BL RADIAL TL
- PSNYX8-ATTACHMENTS, MAIN DRIVELINE THREE SHAFT SYSTEM
- MARZ88-GMC TRUCK
- CCCZY1-COLOR COMBINATION SOLID
- BR_PRDCTgmna-
- CCZZ-
- BRUS-
- MRKT_GMEOPM-
7.8L Duramax LG4, LF8
The 7.8L Duramax diesel, also referred to as the Duramax 7800 and sometimes stylized as the "DuraMax" 7800, is a re-branded variant of the Isuzu 6HK1 turbodiesel found in Chevrolet and GMC medium duty truck applications beginning in 2003 and ending after the 2009 model year when General Motors began its hiatus from the medium duty segment. GM utilized the RPO code "LG4" through the 2007 model year and began using the RPO code "LF8" for 2008 when the 7.8L Duramax adopted a diesel particulate filter. The designations "7.8L Duramax" and "Isuzu 6H" are used synonymously in various GM advertisements, brochures, and spec sheets relevant to applications that offered the Duramax 7800.7.8L Duramax Engine Specs, History, & Information
Unlike the 6.6L Duramax engine family, the 7.8L Duramax is not a result of the Isuzu-GM joint venture, DMAX. The Isuzu built engine was offered in GM applications as part of a separate partnership, General Motors Isuzu Commercial Truck LLC, which was forged in the early 2000's. This joint venture sought to consolidate GM and Isuzu's commercial vehicle lines. Although Isuzu had a strong presence in the segment, one could argue that GM's family of brands were more identifiable in the U.S. markets. Joining forces allowed GM to tap into Isuzu's impressive line of diesel engines, which widely carried positive reputations with regard to reliability and longevity. Furthermore, Isuzu would have an opportunity to deliver more trucks, particularly cabovers, with the help of the Chevrolet and GMC brands. Usage of the Duramax namesake, with regards to the 7.8L Isuzu 6H, was little more than a marketing tactic intent on bolstering sales and increasing the scope of the flagship Duramax diesel brand.The 7.8L Duramax LG4 was offered in one of several tiered output ratings ranging from 195 to 300 horsepower and 441 to 860 lb-ft of torque. Note that the available ratings varied between applications and there are at least 16 different configurations, although only 11 of the combinations were available in Kodiak and TopKick applications, ranging between 200 and 300 horsepower and 520 and 860 lb-ft of torque. The 7.8L Duramax was offered alongside GM's 8.1L Vortec V-8 (RPO code L18) and the Caterpillar C7 (RPO code LG5). The Cat C7 was offered in similar power configurations with a maximum torque output of 800 lb-ft.
When the 7.8L Duramax adopted a diesel particulate filter for the 2008 model year, the RPO code was changed to "LF8" and GM began referring to the engine as the "Duramax" less and the "Isuzu 6H" designation became more common in owners manual and spec sheet references. The engine features a high pressure common rail injection system with solenoid-type fuel injectors and a Denso injection pump. A Garrett variable geometry turbocharger was employed for minimal turbocharger lag and favorable response across the operating range.
7.8L Duramax LG4 & LF8 Specs (Isuzu 6H)
Engine Family: | Duramax 7800, Isuzu 6HK1 (Isuzu 6H) | |
RPO Code: | LG4 (2003 - 2007), LF8 (2008 - 2009) | |
Applications/Production Years: | 2003 - 2009 Chevrolet Kodiak C6500, C7500, C8500 medium duty trucks 2003 - 2009 GMC TopKick C6500, C7500, C8500 medium duty trucks 2003 - 2009 Chevrolet/GMC T-Series cabover WT5500, T6500, T7500, T8500 | |
Displacement: | 7.79 liters (7.8 liters nominal), 475.2 CID (475 CID nominal) | |
Configuration: | Inline 6 cylinder | |
B10 Life: | 410,000 miles | |
B50 Life: | Not specified | |
Bore: | 4.527 inches (115.0 mm) | |
Stroke: | 4.921 inches (125.0 mm) | |
Bore/Stroke Ratio: | 0.92 (undersquare) | |
Compression Ratio [1]: | 16.0 : 1, 17.5 : 1 | |
Firing Order: | 1-5-3-6-2-4 | 
|
Engine Block Material: | Cast gray iron, dry sleeved cylinders | |
Cylinder Head Material: | Cast iron | |
Injection System: | Direct injection Denso high pressure common rail Solenoid type fuel injectors, 7 hole nozzles | |
Aspiration: | Turbocharged, intercooled (air-to-air intercooler) Garrett GT3788LVA variable geometry turbocharger | |
Valvetrain: | Single overhead camshaft (SOHC) , 4 valves per cylinder (24 valve) | |
Valve clearance (lash): | Intake | 0.016 in (0.4 mm), engine cold |
Exhaust | 0.016 in (0.4 mm), engine cold | |
Engine Oil Capacity: | 23.8 quarts with oil filter change Additional engine oil required in vehicles equipped with an auxiliary oil filtration system | |
Lube Oil Filter P/N: | ACDelco PF2203 | |
Fuel: | #2, #1 diesel fuel (includes winterized blends) | |
Peak Horsepower: | 195 hp - 300 hp @ 2,200 - 2,400 rpm | |
Peak Torque: | 441 - 860 lb-ft @ 1,450 rpm | |
Idle Speed: | ~ 600 - 630 rpm | |
Governed Speed: | 2,200 - 2,500 rpm (electronically governed) [2] | |
Engine Weight: | 1,180 - 1,250 lbs (dry) | |
Engine Dimensions: | Length: | 54.61 inches |
Width: | 36.18 inches | |
Height: | 46.46 inches |
[2] - Full load governed engine speed dependent on model year and horsepower/torque configuration.
7.8L Duramax Horsepower & Torque by RPO Code
Note that the availability of power configurations varied with model year and application; some power options are listed as RPO codes in sales material, but could not be connected to any particular model or model year.| RPO Code | Peak Horsepower Rating | Peak Torque Rating |
LPS [1] | 195 hp @ 2,200 rpm | 441 lb-ft @ 1,450 rpm |
200 hp @ 2,200 rpm | 441 lb-ft @ 1,500 rpm | |
LQB | 200 hp @ 2,400 rpm | 520 lb-ft @ 1,450 rpm |
LPU | 215 hp @ 2,200 rpm | "low torque" |
LPT | 215 hp @ 2,200 rpm | "high torque" |
LPE | 215 hp @ 2,400 rpm | 605 lb-ft @ 1,450 rpm |
LQC | 230 hp @ 2,400 rpm | 660 lb-ft @ 1,450 rpm |
LPC | 250 hp @ 2,400 rpm | 660 lb-ft @ 1,450 rpm |
LQS | 250 hp @ 2,400 rpm | 800 lb-ft @ 1,450 rpm |
LYA | 230 hp @ 2,400 rpm | "low torque" |
LYB | 230 hp @ 2,400 rpm | "high torque" |
LYC | 260 hp @ 2,400 rpm | "low torque" |
LYD | 260 hp @ 2,400 rpm | "high torque" |
LQH | 275 hp @ 2,400 rpm | 800 lb-ft @ 1,450 rpm |
LPK | 275 hp @ 2,400 rpm | 860 lb-ft @ 1,450 rpm |
LQF | 300 hp @ 2,200 rpm | 860 lb-ft @ 1,450 rpm |
TG-INPUT (A69)
$195.79 $335.02
SKU 03T38783
Last edited:
