18 speed

Empty, certainly. Loaded...just depends on the terrain and your driving style. Maybe once you learn, you know you'll like to split only the top and not the bottom. Or vice versa.

 

Just remember, the button shifts are not "full" shifts, in regards to RPM difference, but rather half the RPM difference between that and the next full gear.

 

My 379 had an 18 in it and empty I didn't split any and loaded I only split the top.

 

Which is driving it like a 13 speed, which is probably the most preferred transmission for trucks.

 

Yep!

 

empty drive it like a 9 , loaded you should split it like its made for , otherwise you can twist up the main shafts thats why they compound the gears also your milage will go to snot unless you slowly bring up the torque in each gears, it takes a little while to get used to it once you do you wish every truck had one .

 

For upshifts, it is too easy to not use the splitter. All you are doing is pushing the splitter button forward and letting off the throttle to shift, and then when you are moving the shift lever to the next gear you push the button backwards before you do the shift.

When loaded, it makes a big difference on how the truck pulls, as the splitter really lets your engine pull better...having gone from an 18 spd back to a 10 spd, I really notice the difference. A 13 spd is much better than a 10 spd when you are loaded and pulling up hills.

On downshifts, you don't need to use the splitter at all, and if loaded just make sure it is pushed back so you are in the lowest gear at a stoplight.

And as others said, when not loaded, don't bother with the splitter, just make sure when you are in high gear the splitter is forward so you are really in high gear.