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.
It’s not the easiest of transmissions if you are just starting to learn to drive a tractor trailer.
Versatility is the best feature of the 18 speed.
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The driver can always have the right gear to keep the truck engine running at the correct RPM to save fuel and help the truck engine last.
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.
There’s a gear for all situations a driver might encounter.
Shift Pattern For an 18 Speed
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 second, third, fourth, and fifth, then splits up into high range. Then, shift the H pattern again for sixth, seventh, eighth and ninth gear.
- After reaching ninth gear, split up to overdrive for the top gear.
There are plenty of other gears in between, as all main gears have a high range and low range, so that the driver can split any of the gears, twice more.
It might sound a bit complicated at first, but it’s really not.
The more a driver practices, and the more experience he gains, he may find that the gear being used, may not be quite the right one for where he wants the RPM’S to be.
In that case, they can be split up or down accordingly, matching the RPM’S to the engine’s sweet spot.
Drivers who like floating gears should like the 18 speed, as 12 of the 18 gears available do not require moving the shifter, as they are split gears.
Related > How to Float Gears in a Semi Truck
Steps to Shifting an 18 Speed Transmission
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 second, third, fourth, and fifth, then splits up into high range and then shift the H pattern again for sixth, seventh, eighth and ninth gear.
- After reaching ninth gear, split up to overdrive for the top gear.
There are plenty of other gears in between.
Related >5 Tips For Truckers For Effective Use of Cruise Control
18 Speed Transmission Shift Pattern Diagram (Gear Pattern)
This is a very simple basic diagram of the shifting pattern of an 18 speed transmission.
This is the best way to understand the positioning of all 18 gears.
3 Reverse Gears
- There are 3 reverse speeds in reverse. Why? Good question.
3 LO Gears
- 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. (Gears 1,2,3rd position)
In this situation, the 3 low forward starting gears of the 18 speed, are just the ticket to a smooth start.
It’s easy to get a heavy load rolling without abusing the clutch.
15 Forward Gears
- 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.
REMEMBER: Learning to shift an 18 speed transmission pattern is not difficult. Nonetheless, it does take some practice time to shift smoothly.
7 Shifting Tips For Truckers
- Practice. Shifting properly is kind of like riding a bike. The more you practice, the better you’ll get at it.
- Every truck is different. You can have two trucks, identically spec’ed and they’ll shift differently. Every truck shifts just a little differently. It’s like they each have their own personality.
- Find the sweet spot. Just take the time to get to know what your truck likes. Find where the sweet spots are.
- Be methodical. Shifting should be done slowly and methodically. Feather the clutch and feather the fuel to help slide it into gear.
- Shift smoothly. Never try to force a gear. It isn’t necessary. It will slide in virtually on its own if everything is lined up just right (the speed, the RPM and the shifter.)
- Don’t rush. Relax. It’s not something to be rushed.
- Did I mention practice? And yes. Practice, practice, practice.
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F.A.Q’S – Manual Shifting
Yes, there will be a restriction on the CDL, which does not allow you to drive a manual transmission truck. Best to have the ability to drive both a manual and an automatic transmission truck.
Once you learn the ‘shifting pattern’, shifting gears manually is not that difficult. But, it does take practice to shift gears correctly and smoothly, so as not to do damage to the transmission of the truck.
It’s good to have as many qualifications as possible as a professional truck driver. Adding a restriction to your CDL, that you aren’t able to drive a manual transmission truck, lowers your chances of getting a truck driving job. Not all trucking companies have automatic transmission trucks.
Yes, it is possible to shift without the use of the clutch. It’s called ‘floating gears’, by some. Some say it’s hard on the drive line, some say it’s not. There’s no right or wrong answer. Depends who you ask.
Smooth shifting a manual transmission is truly an art. Practicing is the best way to do it properly and smoothly.
This boils down to personal preference. When starting from a complete stop, it’s usually best to double clutch.
