Glad it seems to be working now.
The governor was probably a little sticky... the clue is that it "unstuck" when you put the trans in reverse.
That is a very tell-tale sign that the governor is sticky.
Here's another little old guy trans rebuilder "trick" for you.... if you can stomach doing this....
When the governor sticks/hangs up... let the vehicle roll forward in "D" at a crawl... just 2-3 mph barely moving... and then put the gear shift in reverse just for a second and back to "D". What you do is just kinda "bump" the gearshift from "D" to "R" and back to "D" very quickly.
The slight shock from doing this "snaps" the governor valve free and will often cure a slightly stuck governor. This won't work if the governor is "really stuck".
I have also had good luck using an additive such as LubeGard when valves are only slightly stuck. I generally don't like most additives, but LubeGard seems to be good stuff.