From: Marc Strangfeld (curlyjoe98@yahoo.com)
Date: Wed Nov 10 2004 - 00:19:10 PST
How about an article called
"DOWNSHIFTING WITH COMMON SENSE"
or
"HOW NOT TO DESCEND A GRADE LIKE A MORON"
The cartoon that David posted is very entertaining but
if you read between the lines you'd see that the real
problem is blown engines. Aside from driver
inexperience, the synchronized transmission is partly
to blame for that. The ability to shift to a lower
gear when the engine is already tapped out will cause
the famous destruction we've all heard of. Also, if
the military would move that fancy red arrow back to
2200 or 2300 rpm they would have better luck also.
I have been preached to about the lack of engine
braking in a diesel more than once, and yes I
understand it. But to claim that leaving the truck in
a higher gear to avoid overspeeding the engine will
get you down a hill safer is stupid and reckless.
And, even with my improper driving, I can't recall the
last time I overrevved my M35's engine. Must be luck.
Bjorn, thanks for the experiment. I look forward to a
full report in the next issue of MV mag.
Marc,
weekend driver
of quad axle milk and dump trucks, school buses, boom
trucks, and one lowly old deuce.
--- Joe Garrett <j.garrett@verizon.net> wrote:
> Going down a hill in the same gear that you ascended
> it in is not the same
> as downshifting to decelerate after you are already
> going too fast. A good
> driver anticipates his/her acceleration and
> deceleration in order to avoid
> smoking the brakes or downshifting AFTER losing
> control. A BUS driver has
> to have a very soft touch on both the accelerator
> and the brake pedal. The
> cargo is much more sensitive to abrupt speed
> changes, and can complain about
> a bad ride.
>
> Besides, I only repeated what my former employer had
> stated as policy.
> Since I was a Driver Trainer at that time, I was
> really familiar with their
> policies and the reasoning behind them. They were,
> and still are today,
> correct. Brake shoes ARE cheaper than engines,
> transmissions OR clutch
> rebuilds. As you said, a good driver shouldn't be
> smoking brakes. He also
> shouldn't be smoking clutches, or coming in so hot
> that he needs to over-rev
> a $20,000 engine. I have no opinion on exhaust
> brakes, as I have never used
> one.
>
> I assume your superior attitude about driving skills
> was directed at the
> unwashed masses, the "weekend drivers" of this list,
> since you can tell from
> my note that I am a bus driver. I am only 52 years
> old, and I have only
> been driving busses for 31 years (you have to be 21
> in most states and with
> most insurance carriers to haul passengers). I
> currently own two MC-9
> coaches and a diesel school bus. All are 4 speed
> Allison automatics that
> only lock up in 3rd and 4th gear. Because of this
> lockup situation, I have
> had to actually learn how to DRIVE these coaches. I
> live in the mountain
> west, and am usually hauling high school kids on
> long ski trips, rafting
> trips, or backpacking trips. We have made three
> trips to Alaska in the last
> 5 years and two to Mexico. I can't afford to blow
> up one of these engines,
> or these transmissions, so I just take it easy. I
> shift into 3rd BEFORE I
> start down a hill. I feather the brakes, and I try
> to stay off them as much
> as possible.
>
> The subject of this thread is an M35A2. It has a
> multifuel engine that,
> according to the military, does not respond well to
> engine braking. The
> military says not to downshift it in order to slow
> it down. I have four of
> these trucks, and have driven them thousands of
> miles, much of that in the
> mountains. I have yet to overheat the brakes on any
> of them. They have
> enough rolling resistance that you almost don't need
> to brake except when
> you get surprised.
>
> I think it is a neat project to put an engine brake
> on one, but I will not
> be putting them on my trucks. I am much more
> interested in dual circuit
> brake lines on these trucks.
>
> Joe Garrett
>
>
> -----Original Message-----
> From: jatonka [mailto:jatonka@telenet.net]
> Sent: Tuesday, November 09, 2004 5:43 PM
> To: Military Vehicles Mailing List; Joe Garrett
> Subject: Re: [MV] M35 Exhaust Brake installation
>
>
> What about the instruction in the truck driver's
> manual that says descend
> the hill in the same gear that you ascend it in?
> Isn't that about engine
> braking? What about burning the wheel brakes out or
> glazing them so badly
> that they won't even slow you down on the way to the
> bottom of the hill with
> the school at the bottom at that 20 mph turn? How
> about the signs in all the
> mountain states that say HILL trucks use low gear?
> I am a truck driver,
> have been since I was 15, I'm 53 now. I've always
> geared down, never ran off
> the road to lost brakes, Gone a hundred and eighty
> thousand miles on brake
> linings and never ruined a motor by using Jacbs
> Brake or exhaust brake on
> smaller diesels. I think the weekend drivers oughta
> listen more and speak
> lots less about the driver's world. John T
> ----- Original Message -----
> From: "Joe Garrett" <j.garrett@verizon.net>
> To: "Military Vehicles Mailing List"
> <mil-veh@mil-veh.org>
> Sent: Tuesday, November 09, 2004 12:02 AM
> Subject: Re: [MV] M35 Exhaust Brake installation
>
>
> > Actually the policy on downshifting was "don't".
> >
> > Joe Garrett
> >
> >
>
>
>
>
>
>
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