My steering on my '89 S10 Blazer 4x4 feels a bit loose. Isn't there a way to adjust it to tighten it up? Or do I have to replace the steering gear?

 

ok there's a nut in the steering gear with a allen screw inside losen the nut first and then tighen the allen screw up about 3/4 of a turn or till u feel that is not that loose do not tigh it to much

 

Yes, there is a 5/8" nut on the top of the gear and then tighten the allen screw.
First be sure that the steering is straight ahead as this is the high spot in the gear. If it's off center and you overtighten the gear, you'll be replacing it soon.
So with the front wheels straight, steering centered, you should have at least 1" of play in the steering wheel with the engine running.