As quoted by Jim Shea in one of his many GM steering articles:
"the amber colored GM fluid is the only fluid that has been certified and tested in GM durability test vehicles for millions of miles. It also is the only fluid that have been durability tested in the Saginaw Steering Gear engineering labs for hundreds of thousands of hours. All of the rubber compounds that are used in the seals, hoses, etc in the production GM power steering system are tested in the materials laboratory for compatibility with the fluid.
The GM part number for a quart of power steering fluid is 89020661. The previous GM part number for power steering fluid was 1050017. Both fluids work equally well." http://jimshea.corvettefaq.com/?cat=4
Lee power steering fluid and it's proprietary blend of additives is the oil of choice among many professional race teams. The increased lubrication quality of this non-synthetic fluid is just one of the reasons to use our oil.
Special anti foaming agents and high pressure co-molecules are blended to exact specifications for the best power steering oil period.
Bottled in a quart and gallon sizes, this power steering oil is tested tuff and has conquered the Baja 1000 time and time again, used in all arenas of racing, off road, monster truck, NASCAR, sprint car, modifies and high performance street vehicles, IT GETS THE JOB DONE.