Transmission gear/shaft question

[Kentmac]

In the process of working on the transmission in my model A and need some advice. I am replacing all the bearings and discovered the main shaft (not gear shaft) has some scoring so I ordered a new main shaft and received it from Snyders. The issue I am having is that the gears were difficult to install on the main shaft and do not slide freely back and forth. I put some grease on the shaft and can move the gears by hand but I think they are too tight. Any advice would be appreciated