Ram 4×4 Yukon Spin Free Hub Install

Updated Jan 2, 2015

YukonUntitled-1The Yukon Spin Free kit replaces hub and axle components for improved fuel mileage – and sure-footedness off-pavement.

By Larry Walton

(Photos by Tim Walton/Editorial Services West)

Most of us use four-wheel drive only for the small percentage of time we are on dirt, with some winter driving thrown in. But when we need that bump in traction, we really need it.

Most four-wheel-drive pickups employ a transfer case that lets the driver decide whether or not to put power to the front wheels.

There is a mechanical connection from the engine, through the transfer case to the front drive shaft into the front differential, and out through the axles and hubs to the wheels.

This mechanical connection, with all of its strong steel gears, shafts and U-joints, represents some rolling resistance even when the transfer case has disengaged this part of the system from the engine.

Automatic and manual locking hubs have been in use for decades in order to reduce that resistance by disengaging the wheels from the front drivetrain, improving fuel economy. But not all 4×4 pickup models have hubs.

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This should strike a familiar chord with Dodge RAM pickup owners who have had to look to the aftermarket for locking hubs since 1994. That’s where Yukon Gear & Axle comes to the rescue.


Jason Smalley of Mobile Diesel in Oakland, Oregon, cited concerns about the integrity of the stock unit bearing as the main reason for installing the Yukon Spin Free kit on his 2006 Dodge Ram 2500. Since installing the kit, he feels a lot more prepared for how he uses his truck.

“I’ve got a lot more peace of mind knowing this potential weak link in the four-wheel-drive system is taken care of,” says Smalley who hauls everything from replacement parts to entire diesel engines for the shop his family owns. He also tows a loaded toy hauler on trips to the dunes on the weekends.

And not just to the dunes but out on the dunes. Sand camping with RVs is not for the faint of heart, but the Smalley brothers are up to the challenge venturing well off road with fully loaded pickup and travel trailer ­combinations.

Having a truck you can count on in tough terrain and traction conditions is hugely important.

 Improving Ram MPG

In addition to beefing up the bearing and hub components, Smalley has also realized some improvements in fuel economy with the Yukon setup. His pickup gained 1.5 miles per gallon, which may not sound like much but when you start with 18 mpg that means an 8-percent improvement, which can really add up.

Smalley’s experience echoes what I learned from the guys at Yukon.

“There are several reasons to install the Yukon Spin Free Kit,” says Neal Hollingsworth, Director of Marketing for Yukon Gear & Axle.

“In addition to greater fuel economy and lower maintenance costs, it also increases the strength and durability of the vehicle. By removing the expensive and vulnerable factory unit bearing, fuel mileage is increased and the new tapered roller bearings are much easier and less expensive to service.”

“The addition of 4340 Chromoly outer axles and the all-steel Hardcore Locking Hubs give you increased strength and the ability to manually lock and un-lock the front end,” added Hollingsworth.

Manual-locking hubs also ensure the front wheels are delivering the added traction when it’s needed, where some automatic hubs can have a delay in the wheel locking/unlocking operation. This delayed locking can lead to very harsh engagements and the subsequent breaking of the hub.

 Ram 4×4 Locking Hubs

When it comes to upgrading the Ram 4×4 to locking front hubs, a good shop mechanic and Yukon’s kit makes the five-hour job look easy.

We followed the installation process at Smalley’s shop where most of the install was done with tools that a professional mechanic is likely to have on hand with two exceptions: 1) the Snap-on DHPI for pressing out the unit bearing using the power steering, and 2) a 1 11/16-inch deep spindle-nut socket, which NAPA ran over to the shop during the install.

Master mechanic Matt Johnson of Mobile Diesel took us through the steps to install the Yukon Spin Free components. The step-by-steps show how it’s done.