The 18 speed transmission is strong, versatile and easy to use, once you get the hang of the pattern and if you are experienced with manual transmissions.
For most truck drivers, the 18 speed transmission has more gears than you’ll ever need to use, unless perhaps you’re pulling trains in the mountains or heavy weight.
The 18 speed transmission is laid out in an ‘H’ pattern. The easiest way to become familiar with the 18 speed is to practice shifting in an H pattern.
The driver uses 2nd, 3rd, 4th, and 5th, then splits up into high range and then shift the H pattern again for 6th, 7th, 8th and 9th gear. After reaching 9th gear, split up to overdrive for the top gear.
This is a very simple basic diagram of the shifting pattern of an 18 speed transmission.
There may be times when you’re trying to lift a heavy load from a dead stop. Or maybe you are trying to get a set of loaded B trains going from a dead stop after chaining up on a grade.
There are 15 forward gears in 3 ‘H Positions’. For the average driver, many of these gears will never be used. It depends on the weight of the load, terrain and several other factors.