</font><font color="blue" class="small">( You have a 3 speed rear-end in the tractor with 4 gears in each range, so that gives you 12 forward and 12 reverse. The shuttle up on the dash determines if you are going forward or reverse. For example say if you have the Range shifter in the Mid position, and the gear shifter in 2nd gear, depending on the location of the shuttle (forward or reverse) determines the direction your tractor will travel.
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Adding to what Jon said above. You need to stop to shift between low/medium/high ranges, but the 4 gears in each range can be shifted on the go, forward or reverse (no need to stop to shift)