Engine Oil

Engine oil with the letters CI-4 or CH-4 is best for your vehicle. The CI-4 or CH-4 designation may appear either alone or in combination with other API designations, such as API CI-4/SL. These letters show American Petroleum Institute 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.

Hydraulic Clutch System

Hydraulic Clutch Fluid or equivalent DOT-3 brake fluid.

Windshield Washer Solvent

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

Clutch Bearing Lubricant

Clutch Bearing Lubricant (NLGI #3 consistency).

Exhaust Brake Ball Joint Cap Lubricant

High-Temperature Grease (NLGI #3 consistency).

Power Steering System

DEXRON®-III Automatic Transmission Fluid. Look for "Approved for the H-Specification" on the label.

Manual Transmission

Synthetic Manual Transmission Fluid.

Automatic Transmission

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

Dielectric Silicone Grease.

Weatherstrip Squeaks

Synthetic Grease with Teflon, Superlube.