My dad has a 2005ish Honda Rancher 350ES that sits outside all summer.  He had it tuned up over winter and it starts and runs as good as it ever has but last week decided it doesn't want to go into reverse.  He brought it to the shop today and I expected/hoped the cable linkage going to the transmission for the reverse would be tight but it is loose and moves well.  The microswitch on the top handle also tests open and closed correctly so I don't think that is the problem.  A brief look online says the shift motor could be the issue.  What am I missing?  It it as simple as replacing the shift motor?  Forward shifting works fine up and down.

Also....does a shift motor exist?