GM W-Body vehicles all use a Power Rack and Pinion Steering Gear. The movement of the steering wheel is transferred to a small gear called a pinion. The movement of the pinion is then transferred to mesh with the teeth on the rack, causing the rack to move back and forth. The power steering gear system has a rotary control valve which directs hydraulic fluid coming from the power steering pump to one side or the other side of the rack piston. The rack piston converts hydraulic pressure to a linear force which moves the rack left or right. The force is then transmitted through the inner and outer tie rods to the steering knuckles, which turn the front wheels. A vane-type pump provides hydraulic pressure for the system.
Fluid Level Check
The power steering fluid level is indicated by marks on a fluid level indicator on the fluid reservoir cap. When adding fluid or making a complete fluid change, always use the proper fluid. Failure to use the proper fluid will cause hose and seal damage and fluid leaks. If the fluid is warm; about 150°F (66°C) or hot to the touch, the level should be between the HOT and COLD marks. If the fluid is cooler than 150° F (66°C), the fluid level should be between the ADD and COLD marks.
In conventional, or moderate, climates, use only GM Power Steering Fluid Part Number #1050017 (1 quart size). In cold weather climates, use only GM Power Steering Fluid Part Number #12345867 (1 quart size). Many vehicle owners will purchase a quart or two of GM Power Steering Fluid from an authorized GM dealer so the correct power steering fluid is always available.