Gaffrig shifters
 

One of my drives will not go into reverse. It shifts into forward OK. Is this likely a cable problem and can it be adjusted?

Mine did the same thing last year. For a quick check take off the cable from the shifting (whatever you call it) cable mount in the engine compartment. With the engine running manually shift it I'm guessing you will get reverse. You can try and adjust the linkage at that point (they make a template for this) but it will probably only be a temp fix. What I found was that in the drive there is a piece that the cable claw and the shifting fork attach to one of the holes had oblong out and through the adjustment way off. It is a cheap and easy fix! The new one is made out of a different material and seems to be an improvement.
I know a lot of other things could be wrong (bad things) but maybe you got lucky like I did!:D

Thanks Scott I'll check there first.