v8tvfarmgirl,
If you are planning to remove the countergear and shaft, shown in the exploded view from atomarc, you need a stub shaft to hold the roller bearings in the gear while you assemble the shaft and gear in the case. The counter shaft may be held in place by snap rings, a pin or a bolt- I don't remember on your truck. The stub shaft is nothing more than a short counter-shaft that you use to load the roller bearings into the gear, then you push it out with the 'real' counter shaft. If need be, you can make a stub shaft from a wood dowel. The fit doesn't have to be precise- it only needs to hold the rollers in place while you return the gear and shaft to the case. There is also a set of roller bearings for the reverse idler gear. If memory is correct, the roller sets are different sizes, and a different number of rollers for the two shafts.
I should also point out that the numbers shown in the picture from atomarc are GM group numbers, not part numbers. The group numbers tell which section of the parts manual contains those particular parts. Part numbers then get you the specific part for your application.
Hope this helps.
Harvester
