Advance Gear Reduction: Doubling Down With a Four-Speed Atlas Transfer Case

    A 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. With a 2.72:1 low-range ratio, the transmission output shaft rotates 2.72 times for every one rotation of the transfer case output. This reduction in output speed acts as a torque multiplier, which ultimately allows your rig to generate more tire-turning power.

    If one low-range ratio is good, three sounds even better, right? That's the case we made for our latest 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 isolate 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 transmission, 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.

    Quick Specs
    Our 4 Speed unit was built with 32-spline output shafts and 1350 CV-style yokes. We opted for 1350 for the size and needed the double-Cardan joint due to the operating angles the drivelines will live at.

    More Work, But Moving Closer
    We've still got plenty of work to do, but our Double Cab S-10 build is moving along quite nicely. Soon we'll need to order drivelines and get a fuel cell plumbed. There's also the matter of finishing up the armor and finding a home for our Warn winch. All in good time.