Not sure what model tractor you have, but if it is of any size, and your truck has a stock, or reasonably stock 6 cylinder, you won't need any faster gears, as you won't have the power.
The auxiliary, if it is OD, would be helpful when unloaded or lightly loaded, or if you have more HP available.
At least my 1 ton with a 1955 235, 4.56 gears, and 32" tires was geared about right when I had 3,000 or 4,000 lb in the bed, an OD gear would have done me no good. When empty it would have been a great help.
Grigg
