I just bought a ranger od and a stock 4 speed and the output shaft has a groove in the splines where it mates up to the transfer. Its close to the back of the transmission and maybe a 1/16" deep. Looks like its worn from a seal. Should this be replaced or is this normal? I am rebuilding my 3 speed transfer to go with it and now would be the time to replace this. The gears inside the 4 speed all look ok. Is this shaft hard to replace?