Sounds like a rack to me then. Probably blew out a seal inside.
To pull the rack, most of the work needs to be done underneath. You need to pull both tires, unhook the tie rod ends, unhook the electrical connector going to the rack, unhook the lines going to the rack, unbolt the rack from the subframe, drop the rear of the subframe just a little, supporting it with a jack and pull the rack out one side. I pulled mine out the driver's side.
Install in reverse.
I would recommend getting a used GM rack from Ed or a local junkyard. They are much better than any aftermarket or refub rack from the local parts store.
