Engine Oil

Engine oils with the letters CJ-4 are required for your vehicle. The CJ-4 designation can appear either alone or in combination with other American Petroleum Institute (API) designations, such as API CJ-4/SL. These letters show API levels of quality. To determine the preferred viscosity for your vehicle's diesel engine, see Engine Oil .

Engine Coolant

50/50 mixture of clean, drinkable water and use only DEX-COOL® Coolant. See Engine Coolant .

Hydraulic Brake System

Delco® Supreme 11 Brake Fluid or equivalent DOT-3 brake fluid.

Windshield Washer Solvent

Washer Solvent (Part No. 2-90531-811-0).

Exhaust Brake Ball Joint Cap Lubricant

High-Temperature Grease (NLGI #3 consistency).

Power Steering System

DEXRON®-VI Automatic Transmission Fluid.

Automatic Transmission

See the Allison Transmission® Operator's Manual for correct transmission fluid.

Manual Transmission

Synthetic Manual Transmission Fluid (GM Part No. U.S. 88861952, in Canada 88861953).

Hydraulic Clutch System

Hydraulic Clutch Fluid (GM Part No. U.S. 12345347, in Canada 10953571) or equivalent DOT-3 brake fluid.

Key Lock Cylinders

Multi-Purpose Lubricant, Superlube (Part No. 2-90531-804-0).

Chassis Lubrication

Chassis Lubricant meeting requirements of NLGI #2, Category LB or GC-LB.

Front Wheel Bearings (Except Oil Filled Hubs)

Wheel bearing lubricant meeting requirements of NLGI #2, Category GC or GC-LB.

Front Wheel Bearings with Oil Filled Hubs

SAE 75W-90 Synthetic Axle Lubricant for Medium Duty Trucks.

Rear Axle and Rear Hubs

SAE 75W-90 Synthetic Axle Lubricant for Medium Duty Trucks.

Rear Axle Shift Motor Lubricant

Refrigerant Oil.

Propshafts and Splines

Wheel bearing lubricant meeting requirements of NLGI #2, Category GC or GC-LB.

Cab -- Door Hinges and Latches

Multi-Purpose Lubricant, Superlube (Part No. 2-90531-804-0).

Weatherstrip Conditioning

Weatherstrip Lubricant or Dielectric Silicone Grease.

Weatherstrip Squeaks

Synthetic Grease with Teflon, Superlube.