About 30 years ago and more, tractor fluid was a good substitute for the couple blends of ATF available, but now we have lots of good choices of fluid, and the newer transmissions are much improved for performance and reliability, and you must use the newer trans fluid as recommended buy the factory, especially with their electronic controls.
We used type F and tractor fluid in the early years, but when GM introduced DEX VI, it proved to much better in performance and longevity. The DEX VI would last more than a season of racing compared needing 2 or 3 fluid changes.
For automakers to provide 100,000 mile warranties for truck and cars with HD use in their electronic transmissions, they specified only use the specific type newer fluids.