Why is it a good idea, on trucks that require a CDL license, to shift without using the clutch?

Question

I know you will kill the clutch if you shift all the time using the clutch, but why is it so much different from a normal manual car?

Answer 1

If you pay attention to the manufacturer of the transmission,  (Eaton-Fuller RoadRanger transmissions, which are probably the most popular "brand" name in the trucking industry along with Spicer, Meritor-Rockwell and a few others)  they state that you should use the clutch regardless of the situation because of refinements made in the transmissions now days.  Closer tolerances,  Gear hubs that have smaller splines, but more of them increase the strength of the transmission under load, but also make it easier to do damage if you miss, or force a shift without the clutch.  

Can the new transmissions be shifted without the clutch?  Yes, but they are very unforgiving, which means you need to be right on the dot with the rpms to upshift or downshift.  If you aren't and you "bang" a gear, you can do some serious damage, that will be obvious to a mechanic, as to cause of the damage, when they tear it apart.  

Rule of thumb when shifting a truck.... when in doubt, use the clutch.  

Edit:

One more point that was discussed.  I don't know where someone got the idea that it takes 3 strong men and a boy to push the clutch down in a truck, but they are wrong.  I have trained 90 lbs females to drive a truck and they didn't have any problems.  Granted, when I started in this business over 30 years ago, we walked around with our left legs larger than our right ones, but the new trucks are closer to cars (as far as physical strength required to drive one) than the idea of trucks go.

Answer 2

With the newer     eton transmissions it is best to use the clutch.

Answer 3

You are wrong in several ways!

Many commercial trucks have a Fuller-transmission;this is a gearbox which is not synchronized;it is easier to manufacture,because fairly primitive, and very rugged;If you know your RIG and have a fine ear,you CAN shift gears without using the clutch;but you should not do it.correctly you even have to use the clutch 2 times on each shift.Being not synchronized you need to have the exact cycles per second in your gearbox,or you simply do not get in the next gear;also you need strong legs,because great strenght is required;truckers still like Fuller's,because they tend to have a very long life-span,and as professionals,they can handle it.

In a normal car nobody would tolerate such a primitive thing any more,but normal cars are not designed to live for 1-2 millions miles live-span.

Additionally:Modern clutches you can use as often as you want,you will not kill them!