I talked to the service mgr at local Deere dealer this morning and the first thing he asked was how many zerks were on the sheave on the reverser, and I said only one, he said that's the problem, the later ones have 2 zerks and he said the cams will get dry and lock up and when it gets into a hard pull that will tear up the belt. He said to get the outer sheave half with 2 zerks and grease 1 zerk 2 shots and the other 12 shots. They are recomending greasing them more often now days with this higher yielding corn too.