I remember the older GM vehicles would use Dexron II for PS fluid.
Ref: '02 f-body LS1 in a '92 2wd.
Does the pump on the LS1 use the same???
I bought a non designated fluid and the truck is steering heavy. The fluid is heavier than the Dexron II. I also have a wider tire now that will slow it a bit but shouldn't be this much.