Prep work is a major reason for RSG’s success at building the most reliable transmissions around. The first thing to check is preload of the cluster. The fifth and sixth auxiliary shafts goes in to check preload. Rockland’s Transmission guru, George Kreppein Jr., sets shims in the tailshaft housing before setting it in place. To check endplay, the "endplay plug" is removed at the front of the main case and a rod is inserted with a dial indicator resting on it. George looks for 0.002 to 0.004-inch endplay on the auxiliary shaft and 0.000 to 0.002-inch on the cluster shaft, also referred to as the main shaft.