How to Shift an 18 Speed

1) You can start out in any gear you want, splitter and gear selector be ######.

2) The nice thing about 18 speeds, and their lesser cousins the 13 speeds, is that you can ignore that splitter and use them as 9 speeds. You can completely skip a split shift if you shift later. For instance, to split shift up a gear you usually need to only raise your RPM by around 250. A normal shift in a non-split trans is around 500RPM. So you have the option of either using all your splits, none of them, or some combination of the 2. As long as you are adjusting your RPMs appropriately, it's all up to the driver and what they feel they need.

3) This is correct. The reason splits are used was for heavy loads and engine with tight torque bands. A split allows you to have a narrower range you operate your engine in thereby keeping it in it's torque "sweet spot." It allows, even with more gears, a faster acceleration due to the engine always producing peak, or near-peak, power. But that's not always necessary which is why you don't HAVE to use the splitter, but it's there if you want to. Bobtail, empty and light loads I usually only split the top 3 gears or so. Heavy you prolly only will really do high range. If you need to split the low range you're prolly doing OD loads.

4) Not that I ever noticed. A clutch is a clutch and couldn't care all that much about the transmission it's attached to. It sounds more like a clutch and/or driver issue to me than a transmission issue. (Not saying your don't know how to drive, just that all trucks feel different until the don't and it might be as simply as that for this issue.)

Basically, to shift the 18 or 13 speed you usually start on the low side of the split, in low range. Let out the clutch, start rolling, blah blah. When it's time to shift all you have to do is move the splitter forward, let off the accelerator and the clutch will drop into the high side of the split, then gently get back on the accelerator. This should drop the RPM by about 250 vs a full shift that you have to allow about 450-500 for. Then when you want to shift to the next higher gear you pre-select your shift by switching the splitter back to low side and then doing your normal clutch shift to the next gear slot, again only allowing the RPM to fall 250 or so. It takes some getting used to as you have to quicker with your shifts, but you get the hang out it.

 

An 18-speed is a complicated 13-speed. Use it like a 13 unless you are pulling over 130,000 lbs GVW in the mountains.

Standard shift pattern for 80-100K is 1-2-3-4^5-5O-6-6O-7-7O-8-8O. You'll never need the low-range overdrive gears unless you are on a crazy steep grade and are having trouble getting going (or as mentioned, pulling big weights).

Always start in 1 when loaded (assuming you are driving a truck with a 65mph setup). 2 or 3 is fine when empty.

I drive a 500hp C-15 CAT with a 13-speed and pull B-trains on a regular basis. I never leave Manitoba so I don't need those extra gears.

 

FWIW- I currently drive an 18, and don't even know if I have 1st gear. lol Loaded, depending on the weight, I start off in 2nd or 3rd regular. As mentioned, I rarely split the lower gears unless on a steep grade or extremely heavy. Empty I usually start in 3rd.
@Raezzor 's post is spot on. Only thing I would add.....If you want to split a gear downshifting, you actually pre-select (in this case move the selector back to "regular") while on the throttle, then rev the rpms a bit like when normally floating gears, pop the shifter out of gear, then gently put it right back in gear as the rpms drop.
Everything else has pretty much been covered.

 

See the problem I am seeing with some of these explanations comes down to the truck itself. I drive something different almost every day, many of them are 18/13 sp trannies and all have a different starting gear both empty and loaded. Mainly because I have to take in account what engine and the rear end gear ratio is so I can start in the right gear.

So you can start out in your top range (5th gear low splitter) or you may need to start out in 3rd in low range with low splitter. It all depends on the truck. Even if I am hauling heavy like 110k total weight, I rarely start out in lo (that's for hills or at one customer where I have to pull into the back lot that has a steep hill to climb) or in first because the gearing of the truck makes it a very very slow start.

 

Heh, I always felt the biggest advantage with 18s was a faster reverse option besides high range. I never ever ever split on the low side, and my legal gross weights were 148-164000.

The true advantage is being able to buy a cool t-shirt.

 

I've watched a lot of those "how to" Youtube videos on how to shift an 18. A lot of them incorrectly state that you can preselect your splitter. The splitter has no neutral interlock or synchro like the range does. Preselecting the splitter will cause excessive shift fork and shift collar wear as the splitter cylinder will try and force the split shift the moment you hit the splitter button. Best thing to do is hit the button as soon as you have broke engine torque on the transmission or just a split second before then.

 

I havent driven an 18, yet I have driven 13 speeds. I prefer a 13 over a 10 speed any day of the week. A 13 speed gearing is tighter than a 10.

Imagine a 5 speed lay out that you find in a 10 speed. Reverse is all the way to the left and up. First is straight down from reverse. Now here is the fun part. The instruction I had from 4 different trainers, first speed you can ignore. So you look at it as a 4 speed. It has a hi / low switch just like the 10 speed. Yet you get to ignore first of a ten speed. You just shift the 4 speed, then pop it into high and go to the second gear spot for 6th gear (remember your ignoring the first gear). The trainers I had said unless (like stated above) you are pulling a heavy load, it isnt that necessary for you to grab inbetween gears with the splitter. Use the splitter when you need a way to drop your RPM's to 1500

Mind you this was training I recieved at CR England. I am sure some one will say my training is wrong as it differs from theirs.