On 2012-03-02, Pete C. wrote:

Ignoramus22470 wrote:

On 2012-03-02, Pete C. wrote:

Ignoramus6107 wrote:

I have been practicing and driving my semi tractor almost every day
recently. Not much time every day, but I usually manage to find at
least some time every day. At my age and after 17 years of driving
auto transmission, the skills to drive a truck with an unsynchronized
manual transmission do not come easily, but I am making progress. I
can now shift up and down, and by now, it works well most of the time.

I will soon try to pass a theoretical exam to get a CDL learner's
permit.

i

I'd recommend tracking down one of the "rent our truck for your CDL
test" places that has a semi with one of the automatic (really
semi-automatic) transmissions for your road test. They will have the
proper insurance for everything and having the auto truck will make
things less stressful as well as giving you more points available to
potentially miss on the test and still pass. You can't grind gears (or
run over curbs) on the test, but once you have your license you can
grind the gears on your truck all you want (and everyone runs over curbs
it seems). The test truck rental places also know the test routes and
will guide you through the actual test route for practice before you
take the test. It's well worth the $500 or so they typically charge for
what is typically half a day of their truck and driver's time.

Pete, what are those semi-automatic transmissions, exactly?

I do agree with you, as a matter of fact, about renting something like
that.

i

I only have direct knowledge of the Eaton that was on the Kenworth T2000
I tested on, but essentially they are a regular manual semi transmission
(like 14+ gears) that is under computer control.

There is a clutch that you use when starting and stopping the truck, but
outside of that the computer handles the shifting. There is a
transmission shift that looks a bit like an automatic, but has no PARK
mode and has up/down buttons on the handle as well. Park is handled with
the normal air brake controls which is why there is no PARK on the
shift.

Basically you press in the clutch and shift the lever to D (drive). The
computer will clunk the transmission into gear for you (normally second
gear) and you start moving with the clutch and accelerator like normal.
After you have let the clutch out you just forget about it until you are
coming to a stop. The computer will cut power (electronic throttle) and
power shift for you as you accelerate. There is a display that shows the
current gear it's in. The up down buttons on the shift lever can be used
to force it up or down much like some "sport" cars with automatics.

When you are coming to a stop you brake normally and let the computer
downshift for you as you slow down. When it is down to low gear (second)
you finally push in the clutch as you come to a stop and hold the clutch
down as normal if waiting at a light, or if you are parking you shift to
N (neutral) and set your air brake park control.

They are really quite nice and remove that extra bit of distraction
while trying to merge into traffic on an entrance or exit ramp.
Certainly after you have been driving a manual for a few years that
isn't much distraction, but it is still some and certainly more for new
drivers. From what I read the autos are becoming more common in the big
fleets too.

Just about time, I would say. Thanks for a great explanation.

i