From: geoff@netcom.com (Geoffrey Leach)
Subject: Re: Advice needed on farm/general use truck 
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Tue, 26 Jan 1993 05:31:42 GMT

lovejoy@cantor.math.purdue.edu (Victor W. Lovejoy) writes:

>So our situation is: we need a truck (A Chevy) that can be used for driving
>everyday and gets used like a car, and then has the capability to haul a 
>bed full of hay or maybe a few sacks of grain. We have looked at a 1500 that
>had a bunch of options (used) and it seemed nice. The cruise/air/stereo/power
>features would make my drive to Purdue easy to take, but will a  Chevy 1500 be
>strong enough to haul hay and feed?  I've heard that in order to haul the 1/2
>ton the truck is rated for, special coolers and suspension will be needed. 
>That seems crazy. If the truck will only haul 300 pounds in it's stock conditionwhy don't they call it a Chevy 300 pound truck?

What follows is an edited version of several exchanges of email
between myself and John Cooley (johnc@yuma.ACNS.ColoState.EDU)
concerning the choice of a truck for towing heavy loads -- like tractors.
I thought that it might be of interest in the current discussion,
so I'm posting it, with John's permission.  Responsibility for errors
and omissions lies, of course, with myself.  BTW, its possible to 
tell exactly what rear end a Ford has.  There's a plate on the 
differential.  Any Ford service department can translate the numbers
there into specs.

For what its worth, my conclusion was that the solution to my towing
problem was Ford F-250 with a large V8 and C6 automatic transmission,
with the Ford towing package, from the early 70's.  I actually located
a 1973 longbed with about 100K miles on it for $2500, but hte seller
bugged out at the last moment.  From what I can tell, it would have
been a good choice.  Your mileage may vary.

In article <xvknacj.geoff@netcom.com> you write:
>I need to get a full-size pickup with the capability of towing 5 tons.
>What should I be looking for in terms of engine hp?  Anything else in
>addition to HD suspension and towing package?
>
>And while we are at it, anyone care to reccoment their favorite make/model?
>The budget is $5000, which I think gets me in the early 80s.

5 tons... to me, that suggests 3/4 ton (Chevy 20, GMC 25 or 2500, Ford F250,
Dodge 250) or 1 ton (Chevy 30, GMC 35 or 3500, Ford F350, Dodge 350).  You
should understand and be able to identify a full-floating rear axle.  Most
car salesman won't know anything about this, although many of them will try
to fake it.  1/2 ton trucks never have full floaters, unless a previous owner
has modified the truck.

In terms of the engine, torque, especially between 1500 and 2500 rpm, is far
more important than horsepower.  For a 5 ton trailer, 350 lb-ft or more is 
desirable, which means you'll need a big block (454 in Chevy/GMC, 460 in Ford,
440 in Dodge).

"HD suspension" may or may not mean anything.  Salespeople and owners may
claim "heavy duty" if it helps them sell the truck.  "Heavy duty" relative to
what?  "Heavy duty" 1/2 ton trucks still will not stand up well under your
proposed load.  See if you can get the original window sticker and see
exactly how the truck was equipped.

With a trailer that heavy, most people will experience better reliability
with an automatic than with a stick, although the auto should be the toughest
available in a light truck.  For Chevy/GMC of the years you are considering,
a TurboHydraMatic 400  (THM 400) is the transmission of choice.  I don't know
the transmission spec for Ford or Dodge.  Ford might be C6, if they were still
being made.  No one was making a very strong 4-speed auto in the mid-80s.
You will be looking at 3-speeds.  The transmission _MUST_ be equipped with a
cooler for this kind of load.  The cooler is visible behind the grill in front
of the radiator.  If there is no cooler, then the truck was not originally
equipped for pulling heavy loads.  Manual transmissions are strong, but
require skillful use of the clutch with a big trailer.  If the previous owner
(or you) abused the clutch, it will need to be replaced.  A manual transmission
does not require a cooler.

A 4.10 axle is standard for this type of application.  An axle ratio of 3.73
or less indicates a lighter duty truck.  Fords and Dodges with diesel engines
are exceptions, often having axle ratios around 3.50.  The GM 6.2 liter diesel
is not powerful enough for your application.

The truck will suck gas and be fairly quick unloaded.  The big V8 won't spin
very fast, however, so with the short axle ratio, it won't have much top end.
That's OK.  Also, the short axle ratio causes higher engine speeds than a
longer ratio.  It's easier on the engine and drivetrain for heavy loads, but
the engine will wear out sooner than it might in, say, a big station wagon with
a 2.73 (that's right: 2.73 is common in cars) axle.

Rear axles on light trucks come in two flavors:  semi-floating and 
full floating.  Automobiles, downsized sport-utilities, almost all full-sized
sport-utilities and all 1/2-ton pickups come with semi-floating rear
axles.  Semi-floaters are nice and simple.  Inside the axle housing (the
outside part you see when you look under the truck) there is a shaft.  The
inside end (at the differential) "floats".  It has splines which engage the
output stub from the differential and a bearing that supports it.
The outside end (at the wheel) does not float.  It is firmly and directly
attached to the brake drum and thus to the reast of the wheel and tire
assembly.  The outer end rides on one or two bearings between the shaft
and the axle housing that support the shaft and the weight of the truck.
The semi-floating axle shaft transmits torque and resists the shear imposed
by supporting the truck.  The outside end of the shaft is usually flat, and
is nearly flush with the fact of the brake drum.  

Semi-floating axles also appear on 3/4-ton pickups with GVWRs up to 7,300
lbs.

The next increment of GVWR available will get you over 8,000 lbs, and this
is where full floating axles appear.  In a full floating axle, the shaft
inside the axle housing only transmits torque.  It has no role in supporting 
the truck.  Splines on the wheel end, similar to those at the differential, 
engage the wheel assembly.  The shaft pokes out to the wheel assembly through 
a hollow spindle.  On the outside of the spindle is a much larger diameter set 
of bearings which supports the weight of the truck.  This arrangement generally 
necessitates a substantial hub which sticks out through the center of the 
wheel.  It is common, however, for some kind of hubcap or trim to cover the 
working hub.

Full floating axles also appear on larger trucks, up to and including
tractor-trailer rigs.

This more complex arrangement makes brake work more expensive than on a
semi-floating axle.

On Chevrolet and GMC pickups since 1988, it's easy to tell if a truck has
a semi-floating rear axle (GVWR 7,200 lbs or less) or a full-floating
axle (8,600 lbs and up).  Both 1500 and 2500 model pickups may have semi-
floating axles, but GM trucks with semi-floating axles made since 1988 always
have 6-bolt wheels.  A model 2500 with 8-bolt wheels has a full-floating
axle.  A model 3500 (1 ton nominal, but actual payload as much as 3,500 lbs)
always has a full-floating rear axle.

Fords and GM trucks older than 1988 may have 8-bolt wheels with semi-floating
axles.  Look for the hub.  

Ford and GM both make their own axles.  GM's are often distinguished by the
number of bolts holding the differential cover on.  Ford's are distinguished
by an inch measurement taken somewhere in the center section, and I am not
particularly familiar with them.  The GM 10-bolt and 12-bolt axles are always
semi-floaters.  The GM 14-bolt is manufactured as both a semi-floating and
full-floating axle.  Dodge uses Dana axles.  The Dana 44 is almost always a
semi-floater; the Dana 60 and Dana 70 are full-floating axles.

I suspect I implied that all pickup trucks with 8-bolt wheels have full-floating
rear axles.  This is not true.  All trucks with full-floating rear axles have
8-bolt wheels, as far as I know, but some trucks with 8-bolt wheels have
semi-floating rear axles.  Clear as mud?

The reason why the yard rental operator won't let you tow his tractor away
may have more to do with your Toyota than the hitch that's on it.  It sounds
like you have a class III hitch, which, when installed on a sufficiently
heavy vehicle, will handle 5,000 lbs without substantial risk of breaking.
However, your Toyota is probably rated by the manufacturer to tow 3,500 lbs
or less.  Further, your Toyota weighs less than 3,500 lbs (assuming a 2WD
pickup), and most of it is on the front wheels.  Pulling a 1 ton to 1.5 ton
tractor (2,000 to 3,000 lbs) on a trailer that probably weighs at least
1,500 lbs empty puts you at or over the manufacturer's limit for your truck,
regardless of how strong your hitch is.  This means that the owner of the
rental place doesn't want you to sue him when your clutch dies.  Further,
if the trailer lacks a surge brake (a brake actuated by "pushing" backward
on the hitch, like when you slow down), then it is very easy for the 3,500
lb trailer to push the back end of your little truck around, especially on a
curve, causing you to lose control of the whole works.  The people at the
rental place don't want to be sued for that, either.  Your owner's manual
probably specifies that you have brakes on any trailer over 1,500 lbs.  A
surge brake helps, but electric brakes with a control in your vehicle are
the best solution.

If you have a "heavy-duty" 1-ton Toyota (and Toyota applies these ratings
differently than American manufacturers), it may actually be rated to pull
5,000 lbs (2.5 tons), but you can bet that Toyota requires brakes on a trailer
that heavy.

My Chevrolet Suburban weighs nearly 6,000 lbs empty, and has no special
trailering equipment except for a Class IV drawbar hitch (7,000 lbs gross
trailer weight, and 700 lbs tongue weight) and a transmission cooler.  I have
towed 6,000 lbs without difficulty, but if I were to tow that kind of weight
cross country, I would want a trailer with brakes.  The people at the rental
places, however, are perfectly willing to let me drag a 2-ton tractor home,
simply because my vehicle weighs enough to maintain control of the trailer.

I suggested a configuration based on the idea that you might be towing
something like a large triple axle "camping" trailer, boat or fifth wheel
long distances.  For occasional low-speed towing, you probably don't need
something quite so strong, but you should also be aware that many small
tractors and similar types of equipment weigh more than they look like they
might.  A medium-sized Bobcat loader weighs 6,000 lbs!

How often do you rent this equipment?  Where do you live?  How far is it
from the rental place and over what kinds of roads?

This is relevant.  Our mountain neighborhood has dirt and gravel roads with
grades exceeding 15% in places.  One fellow last year managed to get a
Bobcat down to his house, but his pickup (American full size, 1/2 ton, 4WD,
engine size and transmission unknown) wouldn't pull it back up again.  He had
to drive the pickup and empty trailer to the top of the hill and then walk
down and drive the Bobcat up.  He had no problem on paved roads, but on a
steep dirt road, he needed more weight (for traction) and power than he had.

I wish I had that much land!  Actually, in the road-building business, 15%
(15 foot rise in 100 feet) is _very_ steep.  No year-round county road in
Northern Colorado exceeds this figure.  30-40% is a maximum for an unladen
4x4, and may occasionally occur on a backcountry 4-wheel-drive road.  When
driving a road with a 15% grade, however, it seems much steeper.  30-40% is
plenty steep enough for a blue ski run, although most skiers of such runs
will insist that they are steeper.

  Highways are rarely greater than 7%.  A 7% grade on a highway will be
accompanied by warning signs for truckers.

  Nonetheless, 7% is plenty enough to put quite a burden on a small truck
with a heavy trailer.

  It doesn't really sound like you need a big block engine, unless you like
the idea of more power.  I'd still recommend a heavy-duty 3/4 ton truck with
full-floating 4.10 axles, heavy-duty automatic and towing package.  This
will handle the loads you're pulling and the grades you're dealing with, and
will tolerate some abuse.  It will cost more to run than the Toyota, and may
have some quality control problems, compared to the Toyota.  You should not,
however, encounter any major failures in the engine or drivetrain, and a heavy
trailer will be easier to control than with your Toyota.  You might consider
a beat-up used one, put a little money into rebuilding the important pieces,
get minimal insurance, and only drive it when you need it.  More hassle, but
possibly more pleasant.

  A sway control device is essentially a shock absorber of sorts at the joint
between the truck and the trailer.  It reduces the tendency of the trailer to
sway back and forth at speed.  This is more important as the trailer gets
heavier and the vehicle gets lighter.  A heavy trailer swinging back and forth
behind a light vehicle can kind of take control and cause the whole works to
end up in the ditch.

Patience.  Good 3/4-ton trucks can be hard to find.  They don't change much
from year to year, so their owners tend to keep them, rather than trading
for a new one.

I hope this helps.  It may take a while to find what you want, since many
otherwise suitable trucks will be equipped with small-block (350-360 cubic inch)
engines.  This might be OK, or even preferable, if you can avoid hills and
grades while pulling your trailer.  American trucks are available in so many
different configurations with so many options that many people find it very
confusing to select one intelligently.  Do your research carefully and
understand what you're buying.

People get a lot of work out of trucks with semi-floating axles, but for
serious towing and hauling, I prefer a full-floater, and my next truck
will have one.

-- 
Geoffrey Leach		geoff@netcom.com