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 (Part No. 8-12346-290-0).

Hydraulic Brake System

DOT 3 Hydraulic Brake Fluid (GM Part No. U.S. 12377967, in Canada 89021320).

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 (Part No. 2-90531-817-0).

Automatic Transmission

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

Manual Transmission

Synthetic Manual Transmission Fluid (Part No. 8-88861-952-0).

Hydraulic Clutch System

Hydraulic Clutch Fluid (Part No. 8-12345-347-0) 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.