Re: [A/S] Airstream wannabe looking for tow vehicle information.

["Harvey Barlow" <harveybarlow@xxxxxxxxxxxxxxxx>]

Jim,

A 2500 Suburban with big block 7.4 liter/454 c.i. engine is considered by
many an excellent tow vehicle.  The 3/4 ton Suburban has adequate frame,
suspension, brakes, wheels, tires, etc. to handle the weight and length of
an Airstream in all conditions of weather, terrain, and unexpected
situations.  If it is a fuel injected later-model Suburban you can expect
10 - 11 mpg towing and 14 - 15 mpg light.  The transmission Chevy installs
behind a 454 is normally the TH4L80E, a strong transmission capable of lots
of towing without failure.  It is based on the old TH400.

A Suburban 1500 with 5.3 liter engine will tow an Airstream, but with far
less margin of safety and power.  The 5.3 liter engine installed in the
current generation of 1/2 ton Suburbans and pickups is the old 327 c.i.
motor, recycled to meet federal CAFE standards.  It is a peppy engine when
running light but marginal for towing.  A 5/3/327 is a short stroke design
which makes horsepower at higher rpm, not high torque at low rpm which is
needed for towing.  Chevrolet carefully avoids mention of torque curves in
its advertising literature.  What this means is the engine has to downshift
to lower gears and run at very high rpms to make sufficient power for
pulling steep grades.  You will find that it downshifts for every hill.  The
5.3 is economical when not towing but will actually be less economical while
towing and will wear out faster when used for heavy and frequent towing.
Chevrolet installs a lighter-duty TH4L60E behind a 5.3 liter or 5.7 liter
engine.  They are prone to frequent failure if you use them to tow a lot.

A tow vehicle which is towing at the upper extreme of the manufacturer's tow
rating will not be pleasing for the owner.  I would choose the 2500 big
block Suburban for towing.

Harvey