2017 GMC Acadia Transmission & Axle Gear Ratios

The 2017 GMC Acadia, a popular mid-size SUV, offers a blend of performance and efficiency suitable for various needs. Understanding its transmission and axle gear ratios is crucial for anyone looking to optimize their vehicle's performance, whether for towing, fuel economy, or a balanced driving experience.

Transmission gear ratios

The 2017 GMC Acadia was primarily equipped with a 6-speed automatic transmission, though different variants were paired with specific engines.

6-speed Automatic Transmission (Hydra-Matic 6T50/6T70)

This transmission was standard across most Acadia models, including those with the 2.5L four-cylinder and 3.6L V6 engines. The choice of the 6T50 or 6T70 depended on the engine's torque output, with the 6T70 being the more robust option for the V6.

Available axle ratios

The axle ratio plays a significant role in how the vehicle utilizes the engine's power. A numerically higher ratio provides more torque to the wheels, beneficial for towing, while a numerically lower ratio results in lower engine RPMs at cruising speeds, improving fuel economy. For the 2017 Acadia, the axle ratios were generally set to provide a good balance for its intended use.

How to identify your axle ratio

Identifying the axle ratio on your 2017 GMC Acadia is relatively straightforward. For GM vehicles, the easiest way is to consult the RPO (Regular Production Option) sticker. This sticker is typically located on the glove box door or the driver's side door jamb. Look for a three-digit code that corresponds to the axle ratio. For the 2017 Acadia, you'll likely find codes like GN5 or FW5, which both indicate a 3.16:1 axle ratio. If the sticker is missing or illegible, a GMC dealership can provide this information using your VIN.

Towing vs MPG impact

A vehicle's axle ratio is a direct trade-off between towing capability and fuel economy. For the 2017 GMC Acadia with its 3.16:1 axle ratio:

• Fuel Economy: A numerically lower axle ratio like 3.16:1 allows the engine to operate at lower RPMs at highway speeds. This reduces engine wear and improves fuel efficiency, making it an excellent choice for long-distance driving and daily commuting where fuel economy is a priority.
• Towing: While the 3.16:1 ratio isn't the highest for towing, the Acadia is still capable of towing moderate loads with this setup. For occasional light to medium towing, this ratio provides a decent balance. However, for maximum towing capacity, a numerically higher ratio would typically be preferred, though it was not an option for the 2017 Acadia. Always refer to your owner's manual for specific towing limits and recommendations.

Common issues

The 2017 GMC Acadia's powertrain, including its transmission and differential, is generally robust, but some issues can arise:

• Ring & Pinion Whine: This can manifest as a howling or whining noise that changes with vehicle speed, often indicating wear in the differential gears or improper lash adjustment. While not excessively common in the Acadia, it's a potential issue for any driven axle.
• Carrier Bearing Wear: The carrier bearings support the differential 'carrier' within the axle housing. Wear can lead to vibrations, humming noises, and eventually, differential failure if not addressed. Proper fluid maintenance can extend their life.
• Limited-Slip Clutch Wear (if equipped): Some differentials might incorporate limited-slip mechanisms using clutches. Over time, these clutches can wear out, leading to a loss of the limited-slip function, which might be noticed as decreased traction in slippery conditions. However, many Acadia models simply use an open differential or electronic traction control.

For more advanced diagnostics or repairs, consulting a driveline specialist is recommended.

Find a driveline shop on Repairius.