The Components that Make Up Your Tacoma’s Drivetrain

Knowing what you have to work with is one of the most important steps of a build. You need to figure out your baseline and establish your build plan accordingly. Even if you’re not planning to build your Tacoma, you still want to know as much about the operating system and what it’s capable of.

For newcomers to the automotive industry, the engine and drivetrain can seem like alien technology. Once you understand each unit individually, it becomes much easier to see how they work together though. After you get a general understanding of these components, you can confidently move to upgrade and building the system with confidence.

The engine is the most attractive part of an operating system for many. The displacement and power output of the engine fuels the overall attitude and performance of your Tacoma. The engine is the heart of your Tacoma’s operating system. The engine draws in air and fuel, compresses, burns, and displaces the exhaust in order to produce power.

The circular motion of the crank is generated by the pistons moving up and down in the cylinders. That circular motion is then sent to the transmission which then moves the truck forward and back. 

Many other systems including the charging system and cooling rely on the engine's operation in order to work themselves. The power output of the engine dictates how fast and capable the Tacoma will be.

Tacoma Engines and Power Ratings

• 2.7 I4 - 159 HP & 180 LB-FT
• 3.5 V6 - 278 HP & 265 LB-FT
• 4.0 V6 - 236 HP & 266 LB-FT

Behind the engine in your Tacoma you will find a transmission. Tacoma transmissions arrive in both manual and automatic configurations. With an automatic, a torque converter lives on the engine’s flexplate. This device uses fluid pressure to help control shifting between gears.

With a manual the clutch is mounted to the flywheel. This device is used to separate the engine from the input shaft on the transmission so one can shift through gears. With the use of gears in the transmission, the engine will be able to deliver maximum power at speed.

The gear ratio also allows the truck to reach higher speeds. The input shaft of the transmission picks up rotating motion from the transmission, and this motion moves through the gearbox and then sent through the transfer case. In 2WD, the motion is sent through the driveshaft and out to the rear differential. In 4WD the transfer case sends the motion to the front differential as well.

After the rotating motion is picked up by the differentials, the power is sent out to the wheels. As the driveshaft turns, it turns a pinion gear, which turns the ring gear that turns the axles.

This gear ratio works again to magnify the engines power output. The term differential was coined because of how it allows the tires to move at two separate speeds. With Tacomas you can find two types of differential types: open and limited slip. Open differentials will usually be found within the front housing. In the rear, you can typically find a limited slip.

Open Differentials: This type of differential will send more power to the wheel with the least amount of resistance. These units will not send power through both wheels when at a standstill, but they will when the truck is up to speed.

Limited Slip Differentials: This type of differential will send power to the wheel with the most resistance. At low speeds, both tires will spin. This set up is much more ideal for traction and is generally what will replace an open differential when upgrading.

With a basic understanding of how the drivetrain in your Tacoma, you can move forward with making upgrades to it. Upgrading the drivetrain will amplify the vehicle's capabilities by increasing power output and throttle response.

In stock form, you’ll find that the engines in Tacomas are very capable engines that need very little in terms of modification. They produce ample power and back that power with efficiency. When you start loading up your truck with heavy add-ons for off-roading and work, the engine can start to feel bogged down with the additional weight. By raising the power output, the engine will struggle less and perform as it would, if not better, than it would in stock form.

Cold Air Intake: Engines rely on air intake to produce power. A cold air intake draws in more dense air, which can contain much more oxygen. The additional oxygen will increase power output and may even help with fuel economy. No major gains will be had with these units alone, but they are the first step to take when seeking out additional power.

Computer Programmer: The factory program on your Tacoma is designed to handle a combination of driving types and provide ample power across the board. This is great for daily driving but it will keep some additional ponies in the stable. With a programmer, you can rewrite the stock setting to let those beasts run wild.

Boost: The engines in Tacomas are usually naturally aspirated from the factory. Natural aspiration leaves the engine to rely on vacuum generated by the pistons on the intake stroke to draw in air. With forced induction, you’re jamming air into the chambers. This is a great way to add a ton of power to your Tacoma with one stroke at a time.

The transmissions aren’t a common focal point for aftermarket upgrades when it comes to Tacoma trucks. This leaves most of the factory gearing intact. The differential aftermarket is packed with all sorts of goodies to manipulate and magnify power output to the builder’s tastes.

Carriers: The carrier is responsible for how power is directed to the tires. By upgrading this component, you can greatly increase the traction of your Tacoma.

Many will make this move to break away from the weaknesses of an open differential and maximize traction with the use of limited slip carriers. Many will also move up to locker style differentials to reach the epitome of off-road traction.

Ring Gears: The ring gear is commonly upgraded to improve throttle response. With a lower ring gear, the throttle response will climb through the roof.

It’s also worth mentioning that with bigger tires and added weight, the factory ring gears will suffer and many make this upgrade simply to restore the trucks factory feel.