2021 Toyota Tacoma: Transmission & Axle Gear Ratios

Transmission Gear Ratios

The 2021 Toyota Tacoma was available with two transmission options: a 6-speed automatic (AC60) and a 6-speed manual (RC62F). The transmission paired with your truck is dependent on the engine and trim level.

6-Speed Automatic (AC60F/AC60E)

This is the more common transmission found in the 2021 Tacoma, paired with both the 2.7L 4-cylinder and 3.5L V6 engines.

6-Speed Manual (RC62F)

The 6-speed manual transmission was exclusively available on V6-equipped TRD Sport, TRD Off-Road, and TRD Pro models.

Available Axle Ratios

The final drive ratio, or axle ratio, plays a significant role in the Tacoma's performance, affecting both its towing and hauling capabilities and its fuel efficiency.

How to Identify Your Axle Ratio

Knowing your specific axle ratio is crucial when ordering parts for differential service or when considering a gear ratio swap. Unlike domestic manufacturers like GM or Ford, Toyota makes it a little less direct to identify the ratio from a simple sticker.

1. Driver's Door Jamb Sticker: The most reliable method is to check the manufacturer's sticker on the driver's side door jamb. Look for a line labeled "A/TM" which stands for Axle/Transmission. The code will look something like "B04A/AC60F". The first four characters ("B04A" in this case) represent your axle code. You can then use the table above or consult a dealer to decipher this code.

2. VIN Decoder: Several online VIN decoder services can provide detailed specifications for your truck, often including the axle ratio. While convenient, always verify this information with the door jamb sticker, as it is the most accurate source.

3. Axle Tag (Less Common on Toyota): While common on Ford and Ram trucks, a metal tag on the differential cover bolts is less common and less reliable for modern Toyotas. Stick to the door jamb sticker for the best results.

Towing vs. MPG Impact

The axle ratio has a direct and inverse relationship between towing capacity and fuel economy.

• Numerically Higher Ratios (e.g., 4.300): These ratios are often referred to as "shorter" gears. They multiply the engine's torque more effectively, making it easier to get a heavy load moving from a standstill. This is ideal for towing, hauling heavy payloads, or tackling challenging off-road terrain. The trade-off is that the engine must run at a higher RPM at highway speeds, which leads to lower fuel economy.

• Numerically Lower Ratios (e.g., 3.909): Referred to as "taller" gears, these ratios don't multiply torque as much. This reduces the truck's maximum towing grunt but allows the engine to spin at a lower, more efficient RPM on the highway. This is best for maximizing fuel economy in daily driving and highway cruising.

For the 2021 Tacoma, the choice is made for you based on your engine and transmission combination. V6 automatic models get the more balanced 3.909 ratio, while manual and 4-cylinder models get the towing-focused 4.300 ratio.

Common Issues

The differentials in the 3rd generation Toyota Tacoma are known for their durability and reliability. While widespread "common issues" are rare, a few problems have been reported by a small number of owners, sometimes referred to as the "howling" or "whining" rear differential.

• Ring & Pinion Gear Whine: Some owners have reported a howling or whining noise from the rear differential, typically under light acceleration or deceleration between 45-65 mph. This is often attributed to an improper gear setup from the factory, causing a less-than-perfect mesh between the ring and pinion gears. In many cases, Toyota has addressed this under warranty by replacing the rear differential assembly.

• Carrier Bearing Noise: A failing carrier bearing can produce a rumbling or grinding noise that changes with vehicle speed. This is not a widespread issue but can occur on any vehicle over time.

If you hear any unusual noises from your truck's driveline, it's best to have it inspected by a qualified technician to prevent further damage.

Find a driveline shop on Repairius.