I don't know of a kit that Gleaner makes for a '94 or newer machine. We install a 12.4" pulley on jackshaft when the guys have beans. It works fine in our other crops. You can slow up a bit more by install a clean grain slip clutch pulley from a '92 machine. If shaft monitor lights bother you may be able to tweak the module to get lights out. If not then we modify shaft monitor sensing collar by adding a few legs to it. I know of a dealer that makes a nice slow down kit where it can be quickly switched from fast to slow speed. There are various ways to slow up elevators on older machines.