2015 Toyota Tundra Transmission & Axle Gear Ratios

Transmission gear ratios

The 2015 Toyota Tundra was exclusively offered with a Aisin AB60F 6-speed automatic transmission across all engine and trim levels. This robust unit is known for its durability and smooth shifts, capable of handling the Tundra's impressive towing and hauling capabilities.

Available axle ratios

Toyota offered a variety of axle ratios for the 2015 Tundra, primarily tied to engine choice and driveline (2WD vs. 4WD). The most common ratios you'll find are 3.909 and 4.300. The 4.300 ratio was generally paired with the larger 5.7L V8 to maximize towing performance, while the 3.909 was found with the 4.6L V8, offering a balance of performance and fuel economy.

Note: Axle codes can be found on the door jamb sticker.

How to identify your axle ratio

For your 2015 Toyota Tundra, identifying your axle ratio is a straightforward process, primarily by checking the vehicle's identification label.

1. Door-Jamb RPO Sticker: Open the driver's side door and look for a white sticker on the door jamb. Toward the bottom of this sticker, you will find a section labeled "C/TR/A/TM". The "A" stands for Axle. You will see a code like "A01A" or "A02B". Refer to the table above to match your code to the corresponding axle ratio. For instance, "A01A" indicates a 3.909 ratio with a 2WD configuration, while "A02B" means a 4.300 ratio with 4WD.

Unlike some domestic manufacturers, Toyota does not typically use an easily identifiable metal tag on the axle housing itself for ratio identification on the Tundra. The door jamb sticker is your most reliable primary source for this information.

Towing vs MPG impact

The axle ratio in your 2015 Toyota Tundra plays a significant role in determining the balance between towing capability and fuel economy.

• Numerically Higher Ratio (e.g., 4.300): A higher numerical axle ratio means that for every rotation of the driveshaft, the wheels rotate fewer times. This effectively gives the engine more mechanical advantage, similar to a lower gear in the transmission. The result is increased torque at the wheels, which translates directly to superior towing and hauling performance, especially when pulling heavy loads or navigating steep inclines. The downside is that at any given road speed, the engine will be revving higher, leading to reduced fuel economy due to increased engine work.

• Numerically Lower Ratio (e.g., 3.909): Conversely, a lower numerical axle ratio means the wheels spin more times for every driveshaft rotation. This reduces the mechanical advantage, resulting in better fuel economy at cruising speeds as the engine revs lower to maintain the same road speed. However, this comes at the cost of reduced towing and acceleration capability, making it less suitable for frequent heavy hauling.

Choosing the right axle ratio depends on your primary use for the Tundra. If you frequently tow heavy trailers, the 4.300 ratio is generally preferred. If your driving consists mostly of unladen highway cruising and lighter loads, the 3.909 ratio will offer better fuel efficiency.

Common issues

While the 2015 Toyota Tundra is renowned for its reliability, like any mechanical component, the driveline can experience some common issues over time.

• Ring & Pinion Whine: A persistent whining noise that changes with vehicle speed and often pitch during acceleration or deceleration can indicate wear in the ring and pinion gears. This is typically due to improper gear mesh, lack of lubrication, or worn bearings.

• Carrier Bearing Wear: The carrier bearings support the differential case within the axle housing. Worn carrier bearings can manifest as a rumble or growl, particularly noticeable during turns or when under load. If left unaddressed, this can lead to more significant differential damage.

• Limited-Slip Clutch Wear: If your Tundra is equipped with a limited-slip differential (LSD), the clutch packs within it can wear out over time. Symptoms of worn LSD clutches include a chattering or grinding noise from the rear end when making slow turns, especially if the friction modifier in the differential fluid is depleted or absent.

Prompt diagnosis and repair of any unusual noises or drivability issues related to the driveline are crucial to prevent more extensive and costly repairs down the line. Regular maintenance, including differential fluid changes at recommended intervals, can significantly extend the life of your Tundra's axle components.

Find a driveline shop on Repairius.