How Your Silverado’s Differential Works and Why It’s Important

A differential is a casing (sometimes referred to as the “pumpkin”) that houses a gear train that manages the rotational speed of the wheels. The differential takes the rotational speed from the driveshaft as an input and outputs it to an axle, which in turn rotates the wheels.

There are different types (addressed later in this guide) of differentials that can impact how the wheels actually turn. While turning, some differentials will allow the inside wheel to turn slower than the outside wheel, so that you complete a smooth turn.

It is also worth noting, that when you have a 4-wheel-drive equipped Silverado, that you actually have two differentials, one for the front set of wheels and one for the back. When you engage 4WD, you engage a transfer case that sends some of the power to the front and some of the power to the rear wheels. When 4WD is not engaged, power is only being sent to the rear wheels.

In the Silverado, the two main differential options are locking and open differentials. Typically, the majority of Silverado came with the open differential, however, some Silverados from different years were equipped with an Eaton G80 locking differential.

Open differentials use spider gears, which allow the wheels to vary speeds during a turn, avoiding the wheels skipping or skirting. Open differentials are ideal for the majority of your driving. Should you lose traction with one wheel, the differential will send additional power (not all of the power) to the other wheel to help compensate until you regain traction.

Locking differentials lock up the axles/wheels so that the wheels turn at the same speed, regardless of how much or little traction either one of them has. The benefit of this is that you are able to power out of situations/surfaces where you don’t have much traction, such as when you are off-road.

The easiest way to identify which differential is in your Silverado is to either look at the window sticker or take it to the dealer. However, if you don’t have the window sticker and wish to look it up yourself there are other ways of going about this.

You can use a VIN decoder to identify your differential or you look at the Regular Production Option (commonly referred to as the RPO) list in your glove box. You want to look for the codes that start with “F”, “G”, or “H” as they are an indication of all things gearing and differential related. From there, you would take on of those codes and Google it to see what you have. A common RPO for the Silverado is G80, which is for an Eaton locker diff.

As mentioned above, an open differential is great for daily driving. When one wheel starts to lose power, and open differential sends more power to the wheel that doesn’t have the power to help it get traction. However, the wheel that does have traction gets very little power in comparison. If you are stuck in either mud or sand, an open differential would make it fairly difficult to get unstuck. 

On the contrary, if you have a locker differential, you can lock the axle(s) so that both wheels spin with the same amount of power. That means if one wheel is either off the ground or stuck in the mud or sand, the other that has traction would be able to pull your Silverado out. This makes having locking diffs on your Silverado immensely valuable when off-roading.

An air locker works by either hitting a button or using a level to engage the differential via pneumatic air. This makes it so you don’t have to get out of the driver’s seat and can just switch it on with the press of a button. 

Standard lockers require you to get out of your Silverado and lock the wheel hubs so that both axles rotate in unison. While it isn’t much more work, you do need to exit your truck to engage it. 

Air locking differentials are much more preferred for off-roading as they make off-road traveling much easier.

If your Silverado never touches dirt, then you are more than likely okay to stay with the stock differential. However, if you enjoy going off-road such as driving on the sand or the beach, in mud out in the woods, or anywhere else where there isn’t any pavement, then you will want to go with a more competent differential that can handle the uncertain terrain. A good air-locking differential can be worth its weight in gold when the time comes that you need it; it can be the difference between getting stuck and needing a tow or being able to roll right out of it. 

The final drive refers to the final gear ratio in your Silverado. The final gear ratio is located in the differential housing, making it the jelly (final drive) to the peanut butter (your differential) in your drivetrain. 

The final drive ratio dictates the rate at which the wheels rotate. When you have a larger number ratio such as a 3.73 or 4.10, that means that the engine doesn’t have to work as hard to rotate the rear wheels; a higher ratio is better for off-roading and towing as it provides your truck with more torque then say a 3.31 ratio.

To figure out what gearing ratio your Silverado has you will once again want to look at the RPO list in the glovebox and Google what numbers you come up with.