Understanding Ford F150 Differential Carriers: 2009-2018

There are different types of axles available, and each one’s design dictates exactly how it functions in these scenarios. Deciding what differential you want to use is dependent on what you’re looking to get out of your truck. Rock climbing? Mostly towing? Some light off-road? The differential can make the ultimate difference in your Ford F150’s performance.

We’re going to discuss the most common types of differentials available for late model Ford F150s:

• Open Differentials
• Limited Slip (or LSD)
• Locker Differentials

Open Differentials are very popular amongst passenger vehicles and are considered something of entry level. The Open Differential functions by applying torque to the wheel that has the least amount of resistance. While at higher speeds, or when resistance on the rear wheels is equal, both wheels begin to spin at the same time. However, the differential will apply power to the wheel with the least amount of resistance. Of course, due to this, an open differential has some ailments.

For passenger vehicles on dry pavement, an Open Diff is optimal. It also requires the least amount of maintenance. In less than perfect conditions, such as ice or mud, an open differential isn’t very ideal. Remember that it will put the power to the wheel with the least resistance. This results in the tire with the most amount of grip not garnering any power. So if you have one wheel on rock or pavement, and another on mud or ice, the power will go to the tire in the mud or ice. This is obviously not the most ideal choice for a performance-minded F150.

While shopping, you’ll likely hear the term Limited Slip the most. A Limited-Slip Differential works much the same as an open diff; it is intended to keep the wheels moving equally at different vehicle speeds. But the variance arrives during low traction situations.  Limited-Slip Differentials allow the tires to spin at different speeds, but a system of clutches and springs allow both wheels to receive equal or similar power.

This design helps get one up to speed and lays the torque down much quicker than an open differential, and is better to get out of sticky situations where traction is “limited.” The design’s largest downfall? The Limited-Slip clutches are made of a similar material that you would find on the clutch in your manual transmission. Due to this, these differentials will require more maintenance than an open differential to help prolong the life of the clutches. This means special differential fluid additives are required. And of course, the clutches eventually wear out and need replacing. 

Locker Differentials are a bit more hardcore than Limited-Slip differentials, and they shouldn’t be considered for every truck. Different types of lockers are available, and though they may work with different rear-end mechanisms, the principles are the same. An F150’s Locker will allow tires to spin at different speeds when traction is available, but lock up both tires to rotate at the same speed when traction is limited.

Lockers are effective and low maintenance, but plan to budget more for tires; a Locker rear will eat your Ford F150’s tires quicker than a Limited-Slip or Open Differential. Lockers best suit the off-road enthusiasts who find themselves in sticky situations often.

Open, Limited-Slip and Locker Differentials aren’t the only types you’ll witness on the F150 market—just the most common types. There are other styles, such as spools and torsen (torque-sensing) style differentials. These types are fairly common for serious off-roaders, and it’s worth knowing at least a little bit about them. 

A Spool replaces the entire differential carrier, and is much like a locker. A spool keeps both wheels spinning at the same time, but it never disengages. Spools should only be used on hardcore toy F150s; on the street they will eat up tires at an excessive rate and can be harmful to other mechanical/suspension components. 

A Torsen Style Differential acts as a Limited Slip, but operates with a different style of gears that eliminate clutches and springs. A Torsen unit equates to more cash, but requires little maintenance and will outlive a Limited-Slip Differential. These are growing in popularity and may be the way of the future. But as of now they are like alien technology. 

Upgrading your diff is a big job, and even with the cheapest parts the process can cost a pretty penny. If you’ve read through this list, chances are you’re considering moving to something different like a Limited Slip. But maybe you’re not sure if you already a Limited or Open.

Let’s imagine that you can’t find any casting numbers to indicate what the factory differential is…or maybe you bought the truck second hand and aren’t sure if the previous owner upgraded anything. All you need is a set of jack stands, a jack, and some wheel chocks. 

First, secure the front wheels with wheel chocks and place the truck in neutral. Then, carefully, jack the rear end up and put the jack stands in place to keep the rear wheels in the air. Begin rotating either wheel clockwise. As you rotate the wheel look at the wheel on the opposite side. If the adjacent wheel spins clockwise (same as the wheel you’re spinning), you have a Limited-Slip Differential. If it rotates counter-clockwise you have an open differential, and you should probably consider upgrading if you plan on putting the truck through any hard use. 

Deciding to upgrade your Ford F150’s differential requires an answer to a simple question: are you looking to gain more traction? If you have an open differential and regularly seek additional traction for poor conditions, or have the occasional off-road weekend adventure, moving to a Limited Slip is ideal. 

Also, a Limited Slip is ideal if you’re moving up to a considerably larger tire size or a different ring- and pinion-gear. Moving to a Locker or Spool should only be considered for the more hardcore applications like trucks that see mud and track conditions regularly. 

Replacing these units yourself should only be considered if you have a strong understanding and experience, otherwise consult a professional. These systems are rather complex and require massive amounts of attention to ensure proper operation and a long life. There’s no shame in bringing this job to a professional—especially considering that one wrong move can cost you thousands of dollars and safety.