Only the 4WD drive Tracker is recommended for flat towing, not the 2WD.
It is my understanding that only the 4 wheel drive Trackers are flat towable without modification. The instructions in the owner's manual on 4 wheel drive vehicles specifies that the transfer case be placed in neutral, transmission in park and the steering wheel unlocked. It also specifies that the engine should be started every 200 miles and run for as few minutes with the transmission in drive. Having the 4 wheel drive transfer case is the key feature. Placing it in neutral effectively disconnects the wheels from the drive train.
2013 XTR, Green Gem, 5.0, 3.55 gears.