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 it, 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 driveshaft. 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.
A mechanism for disengaging the wheels from the axles and all of the other parts connecting through to the transfer case would be very helpful. This mechanism, called a locking hub, has been around for a long time. When these hubs are locked, the wheels are connected to the axles. When the hubs are unlocked, the wheels spin free.
Without a mechanism to unlock the hubs from the axles, any turning of the wheels would also turn all of the other parts that connect the wheels to the transfer case. This may sound familiar to Dodge RAM pickup owners who have had to look to the aftermarket for locking hubs since 1994. A number of aftermarket manufacturers have stepped up to fill the need felt by many RAM owners.
Jason Smalley of Mobile Diesel in Oakland, Oregon cited concerns about the integrity of the stock unit bearing on his RAM 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 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 toyhauler 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 is hugely important.
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 18mpg that means an eight 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 lock and un-lock the front end,” added Hollingsworth.
We were there to follow the installation process at Smalley’s shop. The install would probably take about five hours without photographers getting in the way. Most of the install was done with tools that a professional mechanic is likely to have on hand with two exceptions. First was the Snap-on DHPI for pressing out the unit bearing using the power steering and second was a 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 components. Check out the video for how it’s done: