Ron Metcalf, co-owner of National Differential, stocks popular Ford, Dodge, and GM remanufactured transfer cases ready for installation. National Differential’s Mike Snover stands by complete remanufactured rearends in its Security, Colo., location.Builder Walt Lovi works on an AAM rearend for a Chevrolet Duramax-powered pickup.

Southern Colorado repair shop owners open National Differential

Offers wholesale customers quick turnaround with popular reman differentials and t-cases in stock

Security, Colo.—Business partners Mike Snover and Ron Metcalf know how costly a tied up service bay can be. Rather than having a technician rebuild a differential on the spot, the duo says it’s far more profitable and reliable to remove and replace the unit, something they do at their two repair shops, Auto Tech Plaza.

For this reason, the duo opened National Differential last December, marketing wholesale, remanufactured transfer cases, differentials, and complete axle assemblies.

Parts & People visited with Snover and Metcalf at their one-year mark to discuss their progress.

The initial business plan was to offer remanufactured front and rear differential and transfer cases for 4x4, performance, racing, classic applications, as well as OE replacement units for The Big Three trucks and SUVs, Metcalf said.

However, the bulk of the business has ended up being OE replacement units, so much so that many units can be found on the shelf, including Chevrolet’s 246 t-case, Ford’s Borg Warner 4419, and Dodge’s NP-241 manual t-case. 

National Differential shares a 9,000-square-foot building with Auto Tech Plaza on 225 Main St. in Security.  The pair also runs another Auto Tech Plaza location at 1548 S. 21st St. in Colorado Springs.

In Security, Colo., seven service bays are in the front of the building with the remanufacturing operation in the rear. All the stocked units are remanufactured by expert builder Walt Lovi, Snover said, who has nearly 30 years experience working on differentials.

“They bring us the core, we sell them the new one, and it’s done,” Snover said. Unlike competitors who just sell remanufactured units, National has the ability to conduct installations as well, adding some repair shops will sublet the install to them as well. 

“To get a rearend done in a day is saying something,” Snover said. “This frees up our customers’ bays for more profitable work.”

“Their quality and warranty are excellent,” said wholesale customer Scott Frederick, parts manager for Phil Long Ford, a nearby dealership in Colorado Springs.

If a technician tackles an axle job it can be cumbersome to purchase all the parts individually and is time consuming. A complete unit also eliminates the possibility of using the wrong type of fluid, which can cause operating noise and premature wear. 

Lovi uses Yukon Gear & Axle for ring and pinion sets, traction aid differential gears, and axle parts. ARB is also used for diff lockers.

In addition to the remanufactured units, Snover said they also sell parts on their new website, All complete units sold come with a three-year, unlimited mileage warranty. “If the online store takes off like we hope it does, we may have to look at expansion.”

As National strives to service surrounding states and beyond, they use quality shipping crates to safely ship transfer cases and UPS for axle shipment, Snover said. Cores, valued from $350 to $500, can be returned in the crates.

Parts & People

Parts & People is published monthly by Automotive Counseling and Publishing Company, Inc., a Colorado corporation, P.O. Box 18731 Denver, CO 80203, 303-765-4664. President-Lance Buchner. Founded by Lance Buchner and Dave Lucia.