40 OCTOBER 2019 FOUR WHEELER fourwheeler.comADVANCE GEA
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HARSH REALITY WE KNEW COMING INTO OUR ’01 CHEVY S-10 BUILD WAS THAT MOST OF THE
upgrades we would perform would essentially rob the vehicle of power in some
way. While gearing our Dana 60 front and 14-bolt rear axleset with 5.38 Nitro
Gears helped compensate for the 40-inch-tall Nitto Mud Grapplers, the fact
remained that we’d done little to help reclaim or increase the power output of the stock
4.6L engine. Sure, we’ve been very tempted to rip out the original block in favor of a
V-8. However, with only 120,000 miles on the odometer, it seemed like a waste
of a perfectly good (and notably reliable) engine.
So, what’s the solution? Gear reduction. Given that we’ve already maxed
out the numerical ratio possibility in the differentials, the next logical place
to focus on was the transfer case. From the factory, our S-10 came with an
NP233 transfer case. This T-case offered two ratios—1:1 and 2.72:1.Doubling down with a
4 Speed Atlas Transfer Case
By Ali Mansour [email protected] Photos: Ali Mansour
Tech
The 4 Speed Atlas transfer
case is surprisingly compact,
making it a suitable T-case
upgrade for nearly any 4x4. Inside
the 356-T6 heat-treated aluminum
case, you’ll find helical-cut planetary
gears. This gear-style case has proven
to be reliable in off-road race applications,
making it nearly indestructible for our recre-
ational wheeling needs.With a 2.72:1 low-range ratio, the transmission
output shaft rotates 2.72 times for every one rota-
tion of the transfer case output. This reduction
in output speed acts as a torque multiplier,
which ultimately allows your rig to gen-
erate more tire-turning power.
If one low-range ratio is good,
three sounds even better, right?
That’s the case we made for our lat-
est upgrade. It’s an Atlas transfer case
from the gear wizards at Advance
Adapters. The particular unit
we picked up for our S-10 is
its 4 Speed version that offers
1:1, 2:1, 2.72:1, and 5.44:1 ratio
selections. In addition to an overall
strength upgrade over the stock unit,
the versatility of being able to operate
the case in two-wheel-drive low and iso-
late the front axle to help with tight turning
maneuvers will be great on our long-wheelbase
mini-truck. Of course, the increased gear
reduction of 5.44:1 in double low is the main
upgrade factor.
While the Atlas transfer case bolts right up
to the back of our 4L60E automatic transmis-
sion, there’s a bit of work involved getting it
under the truck. Thankfully, our pickup is with
the experts at Low Range 4x4 in Wilmington,
North Carolina. From a custom crossmember
to a one-off center console, we’re breaking
down the critical factors that allowed us to
get this transfer case upgrade in place. Don’t
worry; we’ll have a field report on just how it
works coming soon.Aside from
the fact that we
were looking for more gear
reduction options, the S-10’s
NP233 transfer case needed fixed output
yokes. While you can achieve this by using stock
and aftermarket components from a Jeep NP231, moving
to an Atlas was simply a better long-term performance
investment.