Was just wondering how hard it is getting used to a 13-speed after learning on and always driving a 10-speed? I know all the upper gears are split but do you pre-select with your splitter button like you do going from lower range to high range or do you have to double clutch every time you move the splitter button?

No clutching. Just "burp" the throttle to go between the split gears.

Yes, always preselect ranges and splitters so the transmission has the maximum amount of time to do what it needs to do. I prefer a 13 myself.

The 13 speed is great! It can be a 9 speed, a 10 speed or you can run all 13. You don't have to run all the gears all the time.

A 13 speed is basically a 9 speed. A 9 speed becomes a 13 speed when the overdrive is added to the tailshaft housing to enable it to be able to split all the upper range gears, hence 13 speed. A 18 speed is similiar to the 13 speed except you can also split the lower range and the upper range.

Clutch??? What's that? Is that the thing connected to the 3rd pedal, that gets the truck moving, and keeps the engine running when stopping? That's all i've ever used it for anyway.

no,
you dont double clutch when using the splitter,
you dont use the clutch at all splitting.
assuming 1(low),2,3,4,5(gears).
when splitting up you shall be at high rpm' in sixth gear
then move the splitter forward and release the throttle for about a second, then press back on the pedal gently and you will feel the transmission will be in a higher gear. you will be in seventh gear

then double clutch to 8th gear (assuming you double clutch (( I dont use a clutch shifting))), but do not pre-select splitter, leave it right where it's at, and go into 8th(it's really 9th till you move the splitter down and step on the throttle). (but only move the splitter, after you get the shifter in gear, or you going to hear your splitter grind)your in 8th. now move the splitter down,and then step on the throttle, now you really in 8th,
to go to 9th, you move the splitter forward and release the throttle for about a second, then press back on the pedal gently and you will feel the transmission will be in a higher gear.

you will do this all the way up to 13th gear.
i drive an 18 speed, that lets me split the low gears too.
I just noticed you sig,
and please do not grind um till you find um, lol.

The only thing I can add is, once in a while you do have to tap the clutch to break torque. If you crest a hill and start to pick up speed/RPM you may not have enough throttle to bump it up and then a tap on the clutch will upshift.

In the summer I drive a belly dump with an 18, but very rarely split the bottom half, and empty I just drive it like a 9 speed. In the winter I flatbed with a 10 and I really miss being able to split the top half when loaded.

It's not difficult to get used to. Personally, I've always found it more difficult to adjust from driving a 9/13/18 speed to driving a 10 speed.