2023 GMC Acadia Transmission & Axle Gear Ratios

Transmission gear ratios

The 2023 GMC Acadia offers a single transmission option across all trims: a 9-speed automatic transmission.

Available axle ratios

The 2023 GMC Acadia comes with a few axle ratio options depending on the engine and driveline (FWD or AWD).

How to identify your axle ratio

For General Motors vehicles like the 2023 GMC Acadia, the most reliable way to identify your vehicle's axle ratio is by checking the RPO (Regular Production Option) sticker. This sticker is typically found on the inside of the glove compartment door or sometimes on the driver's side door jamb. Look for a three-character code starting with "G."

• GU6: Indicates a 3.47:1 axle ratio.
• GT4: Indicates a 3.49:1 axle ratio.

If you have trouble locating the RPO sticker or deciphering the codes, a GMC dealership parts department or service center can also provide this information using your VIN.

Towing vs MPG impact

Axle ratio plays a significant role in determining a vehicle's performance characteristics, specifically in the areas of towing capability and fuel economy.

• Numerically Lower Ratio (e.g., 3.47): A numerically lower axle ratio means the engine will operate at lower RPMs at a given road speed. This generally translates to better fuel economy, as the engine isn't working as hard. However, it can reduce the vehicle's ability to accelerate quickly or tow heavy loads, as less torque is multiplied at the wheels.

• Numerically Higher Ratio (e.g., 3.49): A numerically higher axle ratio means the engine will operate at higher RPMs at a given road speed. This increases torque multiplication at the wheels, providing better acceleration and enhanced towing capability. The trade-off, however, is typically reduced fuel economy due to the engine working harder.

For the 2023 GMC Acadia, the difference between the 3.47 and 3.49 ratios is minimal, but the general principles still apply. The 3.47 ratio found with the 2.0L Turbo I4 engine prioritizes fuel efficiency, while the slightly higher 3.49 ratio available with the 3.6L V6 (especially in AWD configurations) is better suited for balancing performance and light towing needs.

Common issues

While the 2023 GMC Acadia's driveline components are generally robust, some common issues can arise with differential and transmission systems:

• Ring & Pinion Whine: A persistent high-pitched whine that changes with vehicle speed (and sometimes load) can indicate wear or improper setup of the ring and pinion gears within the differential. This often requires professional diagnosis and potentially a rebuild or replacement of the differential.

• Carrier Bearing Wear: The carrier bearings support the differential carrier. If these bearings start to wear, they can produce a growling or humming noise that gets louder with speed. Left unaddressed, this can lead to more significant damage.

• Limited-Slip Clutch Wear (if equipped): If your Acadia is equipped with a limited-slip differential (which is less common in this class but possible in some AWD systems), wear in the clutch packs can lead to chattering or clunking noises, especially during turns from a stop. This typically requires replacing the clutch packs.

Any unusual noises or vibrations from the driveline components should be inspected by a qualified technician to prevent further damage.

Find a driveline shop on Repairius.