Hi John,
No reverse can be the Gov, but the other issue usually caused by a blocked or dead Gov is no up-shifts, it will stay in 1st or second only.
Do you have a service manual?
There is a good section on fault finding, it gives a table of issues that you cross reference to causes, works very well.
The Gov is under the rear extension housing, you need to remove the tail shaft, cross member and mount, speedo drive cable drive and shift linkage.
Put a jack and a block of timber under the pan, remove the shaft and mounts, speedo drive cable and drive and shift linkage, lower the trans so you access the bolts.
The extension housing slides off to the rear, the gov is driven by the output shaft.
It is normally the oil supply to the gov, it is fed through galleries in the body of the trans, when these block up with clutch material, the problems start.