Specifications

General Specifications

Engine: GMC 270   with 269.5 cid (4416ccm or 4.416 litres), inline six, ohv (full pressure oil)
Horsepower: 91.5@ 2750 rpm
Compression ratio: 6.75:1
Transmission: 5F 1R  with two speed transfer case
Tires: 7.50 X 20 on most models; others used 11.00X 20 or 11.00×18 singles on both rear axles
Weight: 11,000 lbs for cargo trucks and 11,850lbs for dumps
Gas Tank: 40 gallons (most models)

Fluid Capacities

Radiator: 19 quarts
Crankcase: 10 quarts (oil filter takes 1.5 quarts) 20 weight.
Air Filter: 1 quart 30W or current crankcase oil
Transmission: 13 pints (14 with PTO) 90W
Transfer Case: 7 pints (Split Housing)  4 pints (Banjo Type) 90W
Front Axle Housing: 7 pints (Split Housing) or 13.5 pints (Banjo Type) 90W
Rear Axle Housing: 7 pints (Split Housing) or 17 pints (Banjo Type) 90W

Ignition Specs for GMC 270 cid

Spark Plug Gap: .025
Firing Order: 1-5-3-6-2-4
Point Gap: .018 – .024″
Distributor Rotation: CCW
Initial Timing Setting: 5 degrees BUDC
Intake Valve Clearance: .012 – hot   (older models below 270-11344 use .006)
Exhaust Valve Clearance: .012 – hot  (older models below 270-11344 use .013)

Parts Reference
Item Replacement Part Notes
Oil Filter NAPA 1503 Available from VOV
Gas filter NAPA 3042 This will fit perfectly in the original filter case.  Just put a medium spring under it to keep the seal. In-line filter also recommended.
Spark Plugs AC  R45 or AC 44
Champion  J8
14 mm
Plug Wire Set NAPA 700173
Points NAPA CS763A (same as Chevy 235)
Distributor cap NAPA RR95 (same as Chevy 235)
Rotor NAPA RR83 (same as Chevy 235)
Condenser NAPA  RR174 (same as Chevy 235)
Coil (6V) NAPA 29730 (same as Chevy 235)
Fan belt NAPA 25-28437 For the 7/8 fan belt
Top radiator hose Gates 21942 Cut to fit
Lower radiator hose Any 1 1/2″ Cut to fit
Brake Cylinders Available from VOV with stainless sleeves
Go to parts
Front left must be rebuilt to clear knuckle.
Brake Shoes Available from VOV
Go to parts
Master Cylinder NAPA # 2842 Available from VOV with stainless sleeves
Go to parts
Hydrovac Bendix 2510296 Replacements available from VOV
Front wheel bearings Same as Chevy(Jim Carter ME390)
Rear wheel bearings Race for inner wheel bearing 394CS
Race for outer is 382
Front axle seal

Banjo axle same as Chevy

Available from VOV
Rear axle seal Available from VOV
Front Knuckle Seal Same as Chevy on Banjo Axles
Thermostat Temp Guard B-306
1/4 X 20 X 3/4″ clutch head screws Filling Station # GM1251 Available from “The Filling Station”
Front knuckle seals (All seals also available from von Rosenthiel)
Valve grind gasket set NAPA HS1935S Thanks to Mark Norman
Full overhaul gasket set NAPA FS1935S Thanks to Mark Norman
Exhaust manifold donut NAPA F7139 Thanks to Mark Norman
Windshield  Rubber for Open Cab Beechwood Canvas #B2042-R Lists it is for Dodge, but fits nice.  Cement ends together

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Vehicle Identification
Year of design Type Front Wheel Drive Rear Wheel Drive Longer than standard wheelbase
A – 1939
B – 1940
C – 1941
D – 1942
C – standard cab
F – Forward cab
U – Amphibian

K

W

X


Examples
CCKW = 1941 truck with standard cab, front and rear wheel drive
DUKW = 1942 designed truck with amphibious capabilities and front & rear wheel drive

Symbols

Meaning

CCKW 352
CCKW 353

A
B
C
D
E
F
G
H

1
2

short wheelbase
long wheelbase

cargo body w/o winch
cargo body w/ winch
stake wagon
gasoline tanker w/o winch
gas tanker w/ winch
van body
water tanker w/o winch
dump with winch

Split axles
Banjo axles

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Classic "Split Axle" also known as Timken Axle

CCKW Axle Types

Split Axles: These look a little like two funnels bolted over a ring gear.  They share the same REAR brakes as Banjo axle GMC and the Chevy 1 1/2 ton trucks.  The front shoes and cylinders are different. About half the CCKW’s had split axles.  These were made by Timken as GMC could not keep up with producing the quantities needed of their own banjo axles.

Banjo Type Axles: These split parallel to the axle shaft and look similar to modern rear differentials.  They are used on all Chevys and 50% of the CCKW’s.  The FRONT axle is the same as the Chevy except for the U-joint yoke and steering ball.  They share the same bearings/seals/brakes, etc. The Banjo axle is considered to be the stronger of the two.

Sources:
Standard Catalog of Military Vehicles 1940-1965, Thomas Berndt, 1993
TM10-1127 Chevrolet Maintenance Manual 1 1/2 ton Trucks 1941
US Military Wheeled Vehicles, Fred Crimson, 1983

Vehicles of Victory Portrayal Press
The GMC – A Universal Truck Jean Michel Boniface
Note: More information can be found in the “GMC CCKW Owner’s Guide and Illustrated Parts Directory” available exclusively from VOV.  Go to the “manuals” section for order info.