6 This is very important when installing a torque converter. And in fact, Curt Thomas from Monster tells us that this is where most gearheads screw up a backyard trans install. As you can see, there are two sets of splines on the input shaft, along with a green O-ring. There are a couple of ways you can cause yourself issues. First, if you're not careful and you don't grease that seal you can knock it off, causing a nice little leak once everything is bolted up. Second, the pump stator (which Curt is pointing to) centers the converter so that it spins true.