When Isuzu released the venerable Trooper to America it jolted
the growing SUV market. The boxy, utilitarian 4x4 that comfortably
hauled 5 passengers plus all of their gear was long on value.
In the process of its evolution, the truck soon garnered the most
votes for three years as Motor Trend's 4x4 of the Year. It did
that not only by being rugged and economical, but by striking
a balance in its design. The IFS provided good on-road handling,
while trading off some of a solid axle's trail potential. Accordingly,
its gearing was chosen to pass easily between service in both
types of jungles- asphalt and dirt.
in the manual transmissions was typically 3.77:1 (in comparison
to the Jeep WranglerTJ's current 4.04:1), while axle ratios in
Troopers, Rodeos and other models were either 4.10, 4.30, 4.56
or, in a few vehicles, even 4.77s. While these ratios are certainly
respectable, their potential was limited through the use of 2.05:1
transfer case low range (compare this to a TJ's 2.72:1). The result
was a crawl ratio, at best, of 37:1.
owners of Isuzu 4x4's would find 1st gear and 4Lo to be plenty
capable, most owners, as with any SUV's, are not trail enthusiasts.
So it was the pioneering individuals in the Isuzu OHV community
who sought solutions to the problem of too much speed and too
little control while on the trail. A few people swapped engines
and transmissions via the now defunct Advance Adapters kit for
4.3L Vortec motors. Many sought out the hard-to-find 4.77 axle
gears that came with option code SL2, the so-called Big Tire Package
(31x10.5" and honeycomb aluminum rims). A rare few went so
far as to swap in Toyota front axles and transfer cases equipped
with Marlin Crawlers.
All of these
solutions worked fine for the enterprising souls who put themselves
on the bleeding edge of innovation. However, the average 4x4 enthusiast
(if there is such a person) is not interested in such one-off,
expensive experiments. As with any marketplace, such unmet demand
drives businesses to get busy and come up with solutions. For
the Isuzu aftermarket, this happened in 2000 when Tera
Manufacturing (Utah) stepped up to the plate by putting the
first ever aftermarket low range gear set for Isuzu's into R&D.
The process saw the first prototype installed at the end of the
year and production units shipped the following autumn.
Fits 1987*-1992 All models. Transfer case uses a rear, slip-yoke
Fits all models 1993-1996.Transfer case uses a fixed-yoke
Fits 1997-2001 with automatic transmissions only.
Fits 1997-2001 with 5-speed manual transmissions only.
My first encounter with the teralow 3.07 gear set (other than
the enormous clamor generated by the online Isuzu communities!)
was at the Moab 'ZuZoo IV in May of 2001. At this event, the largest
off-road gathering of Isuzus in the Americas, were four vehicles
that had been equipped with Tera's new 3.07:1 gears in their transfer
those rigs slowly pick and choose their lines was apparently all
one had to see to know that this was THE mod to get. I listened
with growing interest to trail reports from those envious onlookers
who watched one or more of the Tera-equipped rigs. Soon it was
my turn to gawk.
Fernando Rivero on the Moab Rim trail in his Amigo, which served
as the test mule for the prototype gears, for a day. On obstacles
where I was putting the WomBAT's Lock Right and ARB Air Locker
to full use, along with the umph of its tweaked 3.4L Camaro V6,
Fernando was able to slowly and nimbly ooooze his way up, only
occasionally relying on his own ARB. Yes, he was an excellent
driver. Yes, his Amigo was a lot lighter, but those gears!
I wasted no
time falling in behind Fernando's Amigo. Not long after doing
so, I weaseled my way into its driver's seat. With the WomBAT
in the rear view, I got my first taste of the control and capability
that Tera's gears afford. It was immediately apparent that the
3.07:1 ratio yielded a gear reduction that felt like a full gear
lower than stock. In sharing this impression over the CB, I soon
found out that his Amigo was only sporting 4.56 axle gears. I
was used to 4.77s! Correction: Make that more like two full gears
the remainder of 'ZuZoo I was able to watch and talk with the
other Tera owners. All of these were Amigos or Rodeos, and none
were manual transmissions. Upon my return, I immediately began
looking into the prospect of installing the gears in the WomBAT.
I had come away with feeling that the gears rivaled, if not exceeded,
the benefits of the rear ARB Air Locker that had for so long been
considered the single best off-roading modification available
for our trucks. Fortunately, Jeff Mock and the rest of the crew
at Tera again stepped up to the plate and provided a set of the
3.07's to review.
The gear set
arrived in an extremely well-protected bed of dense foam, with
each element fitting snuggly into its pre-cut slot. Accompanying
the three-piece kit (new idler gear, low speed clutch drive and
shift rail) were a set of clearly-typed instructions and the ever
important "Tera Inside" sticker, whose Intel mocking
even a Mac guy like me could appreciate. The two pages of instructions
offer a step-by-step description of the assembly and disassembly,
coupled with an exploded view of the transfer case from the Isuzu
factory manual. Following several discussions with colleagues
who were running the Tera gears, I opted to take the whole shooting
match to our local transmission specialist (aptly named Transmission
8385 S. Allen St., Unit 115
Sandy, UT 84070