* Gear selected: You'll be at a much lower RPM in 5th gear than in 3rd gear at 60 mph.
* Tire size: Different tire sizes change the rotational speed of the wheels for a given vehicle speed.
* Differential gearing: Different gear ratios in the differential will affect RPM. Some Trackers had different options.
To find the RPM, you'd need to know the gear ratio of the 5th gear, the differential gear ratio, and the tire size of your specific Tracker. Then, you could use an online calculator or formula designed for this purpose. Many such calculators are available with a quick web search for "gear ratio calculator."