Jake, I've never fooled with a gmc v6 but that looks like any other harmonic balancer. Go to AutoZone and rent a puller, tell them you want to pull the harmonic balancer off the crankshaft. They will rent/lend you the tool.It bolts to the holes on the balancer/pulley and there is a bolt in the center that pushes against the cranksaft and pulls the pully off the crankshaft. If the crankshaft has threads on the inside you put a bolt in there and it will pull the new pulley back on the crankshaft.
Before you start look to see if there is a bolt holding the pulley to the crankshaft in the center, if so remove it then install the puller.
