First item to check is trans fluid level. Not easy to do as the "dipstick" is built into a plug at psgr side of transmission. Search YouTube for DIY videos. How many miles on your Trac, and has transmission ever been serviced?
If it were my truck I'd do a full flush, then drop the trans pan, change filter, top up. Some might say wrong order, but to me doing that way protects a new filter from contamination. For sure it's a messy DIY job, but if you shop around you might get a reasonable price. Check out AMSOIL fluid choices on my website.
Members here that report in with 100K, 200K or more on their Tracs have one thing in common: They've taken care of their cars by doing more services than recommended, especially with transmissions. ATF is complex fluid because it has to do multiple things - cool, lubricate, transfer power. The better shape it's in, the better job your transmission does with long life.
Thought this was a very cool machine. Has no power and uses the vehicles own transmission pump to replace the fluid. I requested NO cleaners or additives be used.
Local dealer did the complete service including 20 QUARTS of Motorcraft Mercon V, filter, and gasket for $199. Would have paid that for fluid and parts alone, let them do it.