Silverado Drivetrain Components and How They Work

When you refer to a Silverado’s drivetrain, you are referring to the following parts:

• Transmission
• Clutch
• Torque converter
• Flywheel
• Flexplate
• Driveshaft
• Axles
• Gears 
• Differential 

It is worth noting that when it comes to automatic transmission equipped Silverados, you will have a torque converter instead of a clutch and vice versa. When you have a manual transmission Silverado you will have a clutch instead of a torque converter.

In addition, flywheels are only in manual transmissions. Automatic transmission equipped Silverados use a flexplate. Flexplates are not a typical or common upgrade for automatic transmissions.

As the engine generates power, it goes into the transmission. Now, if it is a manual transmission and it is in gear, then you would let off the clutch as you press on the gas, which would engage the clutch and flywheel sending power to the driveshaft. If it is an automatic transmission and in gear, then you would remove your foot from the brake and the power would transfer through the torque converter and flex plate to the driveshaft. 

As the power makes its way down the driveshaft it would go into the differential housing and engage the differential. The differential causes the final drive gears to spin, which rotate the axles, causing your wheels to turn. While this is a simplified and straight forward explanation, without going on a long tangent, this is the general synopsis of what happens from the moment you hit the gas to the moment the wheels start turning.

Drivetrain loss is a term used to refer to the amount of power that gets lost from the engine to when it hits the rear wheels. Almost all auto manufacturers, including GM/Chevrolet, dyno test their vehicles at the engine (mainly because the power number is higher). When you put your vehicle on a rolling dynamometer, which measures the power at the wheels, you will see a 10-18% loss in power from what was noted at the engine. This is normal, so don’t freak out and think you got a dud from the dealer. 

You can reduce/minimize the amount of power that gets lost in the drivetrain by replacing the stock parts with lighter, more efficient ones that have less rotating mass. Essentially, less rotating mass means less work the engine has to do to turn those parts that put power to the wheels.

Transmissions can be a tricky part as they are arguably the most expensive part of your whole entire drivetrain. When you replace an automatic or manual transmission in your Silverado, you are looking at spending anywhere from $2,000 to $10,000 dollars along with some customization work depending upon the transmission and other modifications (to the exhaust system or suspension).

The main reason you’d want to upgrade your transmission is if your stock one blew up or you are building up your Silverado to hold more power. For instance, if you add either a supercharger or turbocharger to your 8-cylinder Silverado, you will want to consider going with a trans rated for the power you are putting down, like a Tremec or Powerglide. 

The stock transmission does a fairly good job at holding power and more often than not, you will be better off just leaving the stock transmission alone and upgrading the other supporting parts.

Clutches in manual Silverados and torque converters in automatic Silverados are an integral part from taking the power of the engine and getting it to engage with the transmission. The main purpose of both the clutch and torque converter is it transfers the power when engaged and spins independently from the rest of the drivetrain when stopped. 

Manual owners can upgrade to a thicker, stouter clutch able to hold more power. Too much power going through the stock clutch will cause it to explode, so make sure you have a clutch rated for the power numbers you are making. 

Automatic owners can upgrade their torque converter for the same reasons as those listed above. A more robust torque converter will hold more power while allowing your Silverado to shift more aggressively.

Manual Silverados use a flywheel to connect the clutch to the transmission, transferring the power to the transmission. Automatic Silverados use the flexplate to connect the torque converter to the transmission. Typically, flexplates are much lighter than the flywheels found in manual cars. 

In both cases, you can replace the stock flywheel or flexplate for a lighter option typically made from billet aluminum. Reducing the weight of the flexplate or flywheel will allow for more power to transfer from the engine to the rest of the drivetrain more smoothly.

The driveshaft takes the power from the transmission and sends it to the differential. The main reasons for upgrading the driveshaft on your Silverado is because you want something lighter (reducing drivetrain loss) or because of other modifications such as a lift kit (to correct the geometry of the suspension).

A lighter driveshaft will typically be aluminum or carbon fiber verses the iron the stock one is made from. This will give you a small bump in power at the rear wheels. If your Silverado is lifted, you will want to get a driveshaft that corrects the new suspension geometry. Usually, this means getting a longer driveshaft to adjust for the increased distance from the transmission to the differential.

The axles connect to the differential housing and the wheels. The main reason for upgrading the axles is because you have added power to your Silverado and don’t want to risk breaking the stock ones, or if you are into off-roading you will want something that can take more of a beating. 

Typically, axles are not a very popular upgrade on the Silverado, but there are options available. A stronger axle is never a bad thing, no matter the vehicle and will just give you more peace of mind in the long run.

When talking about gears, one is typically referring to the rear or final gears in a vehicle. Sometimes called the final drive ratio, the rear gears impact the acceleration and top speed of your Silverado. Going to a steeper (higher number) gear will give you quicker acceleration, but lower top speed. 

Conversely, going with a lower (smaller number) gearing ratio will increase the top speed and spread out the shift points. Boosted Silverado owners will benefit more from lower ratio final gears than naturally aspirated Silverado owner who will benefit from a steeper final gear ratio.

A differential dictates how the rear wheels are engaged. There are different types of differentials such as:

• Open 
• Limited-Slip
• Locking/Torsen

Open differentials allow the rear wheels to turn at different speeds and is the most common type of differential, even found in your Silverado. 

Limited-slip differentials are essentially an open diff, but with a spring pack and set of clutches. This addition allows for better torque vectoring and for more power to transfer to one wheel or the other.

Locking differentials are the main choice for off-roaders as it allows you to lock the output shaft and get both the rear wheels to spin together at the same time. A Torsen differential uses a torque bias to send more power to one wheel or the other depending upon how much traction the other wheel has. If the bias is 7 to 1, then a Torsen diff can send up to 7 times as much power to the wheel that has traction when the other loses it.