What's the difference between transmissions?

Usually the trucks with 18 speeds...they're made for OTR, get the RPM's as low as possible at cruising speed. Rear end ratios come into play as well.

 

Different gears for differnt loads and/or terrains. 18 spds are more prevalent in heavy haul where you need deeper gears to get the weight rolling. OverDrives are more for highway running to keep the rpms lower at cruising speeds. The others fall in the middle for different applications.

Because the trucking industry is so large and diverse there's really no "standard" transmission choice.

 

I would guess most company trucks use the ten-speed. Not positive.

 

Many are going automatics because they think you newbies are too stupid to learn how to shift.

 

Most standard OTR companys use the 10 or 9 speeds. 18 and 13 spds are for heavy hauling and allow for greater rpm control up and down hills, with the 18 as the king for getting somehing heavy rolling. These add an additional splitter on the gears, IE: 8 low/hi. There's also the Super 10 which from what I understand is a 5 spd using a splitter (I may be wrong on that one).

When I get my own rig, I'll aim for the 13 for the increased control on hills.

 

I drove a KW that belongs to a friend of mine with a CAT motor and the 13 spd. I learned with a 10 but I really liked the 13. A lot easier on the hills.

 

The two companies that i drove for used 9/10 speeds.

 

The 15 IMHO is a totally useless OTR transmission for regular hauling. I will take a 13 anyday.

 

Wanna-be here, so ......aside from stopping and taking off, is shifting just a matter of modulating the throttle and not necessarilly the clutch with each gear through; never seen a driver actually do the shifting to see the procedure.

Thanks!