CLEVELAND FELT GREASE SEAL 154-00600

There is no difference between 40-78 & 40-78B, they are application specific. The 40-78 are on Cessna and the 40-78B are on some American Champions, Pitts, etc. Looking at the parts breakdown for each assembly, they do have the same replacement parts. Both units will need qty 2 cup bearings per assembly. One for each half. The part number for the cup bearing is 214-00300.