2018 Nissan Titan: Transmission & Axle Gear Ratios

Transmission gear ratios

The 2018 Nissan Titan (and the heavier-duty Titan XD) simplifies things by using a single, robust transmission across the entire model line.

Jatco JR711E / RE7R01B 7-Speed Automatic

Available axle ratios

Nissan offers several final drive ratios for the 2018 Titan lineup, tailored to the vehicle's intended use, engine, and drive configuration (4x2 or 4x4). The ratio determines how many times the driveshaft must turn to spin the axle shafts one full revolution.

How to identify your axle ratio

Knowing your specific axle ratio is crucial for ordering the correct parts or understanding your truck's capabilities. Unlike some domestic brands that use easily accessible RPO codes on a door sticker, identifying a Nissan's axle ratio can require a little more investigation.

• Vehicle Information Sticker: Check the driver's side door jamb for a sticker that contains vehicle details like GVWR, paint code, and build date. In the "AXLE" or "TRANS/AXLE" section, you will find a code. For these Titans, common axle codes include:
  • RA93: 2.937:1
  • RD33: 3.357:1
  • RG36: 3.692:1
• VIN Decoder: Numerous online VIN decoder services can provide a detailed build sheet for your specific truck. This is often the most reliable method, as it pulls the exact configuration from Nissan's database. It will list the final drive ratio among the vehicle's specifications.
• Axle Tag (If Present): While less common on modern vehicles, some axles have a small metal tag bolted to one of the differential cover bolts. This tag may be stamped with the ratio (e.g., "3 36" for 3.36:1), but road grime and corrosion can make it difficult to read.

Towing vs MPG impact

The axle ratio is a fundamental component of your truck's performance, creating a trade-off between pulling power and fuel efficiency. The concept is straightforward:

• Numerically Lower Ratio (e.g., 2.937:1): This is considered a "taller" gear. The engine runs at lower RPMs at highway speeds. This is better for fuel economy as the engine is under less strain during cruising. However, it provides less mechanical advantage for towing, meaning the engine has to work harder to get a heavy load moving.

• Numerically Higher Ratio (e.g., 3.692:1): This is a "shorter" gear. The engine runs at higher RPMs at any given speed. This provides a significant mechanical advantage, making it better for towing, heavy hauling, and quicker acceleration. The trade-off is reduced fuel economy, especially during highway driving.

For the 2018 Titan, Nissan paired the ratios logically. The standard Titan gets the taller 2.937:1 ratio to maximize MPG for daily driving. The Titan XD, designed for more demanding work, gets the shorter 3.357:1 (Cummins) and 3.692:1 (Gas) ratios to enhance its towing and hauling prowess, which are key selling points for that model.

Common issues

The driveline in the second-generation Nissan Titan and Titan XD is generally considered robust and reliable. However, as with any truck used for towing and hauling, certain issues can arise over time with high mileage or heavy use.

• Ring & Pinion Whine: A whining or howling noise that changes pitch with vehicle speed (but not engine RPM) can indicate a problem with the ring and pinion gear set in the differential. This can be caused by improper gear setup (backlash/preload), worn bearings, or contaminated fluid.
• Carrier Bearing Failure: The driveshaft carrier bearing, which supports the multi-piece driveshaft on longer wheelbase models, can wear out. This typically presents as a vibration or a rumbling noise from underneath the center of the truck, especially during acceleration.
• Limited-Slip Clutch Wear: On models equipped with a limited-slip differential (LSD), the internal clutch packs can wear out over time. This will result in the differential behaving more like an "open" one, where one wheel can spin freely if it loses traction. This is often noticed during tight, slow turns (chattering) or in low-traction situations.

Proper and timely maintenance, including using the correct type and weight of differential fluid, is the best way to prevent these issues.

Need to diagnose a noise or service your Titan's drivetrain? Find a driveline shop on Repairius.