2018 Toyota Tundra: Transmission & Axle Gear Ratios
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Transmission Gear Ratios
The 2018 Toyota Tundra comes equipped with a standard 6-speed automatic transmission across all trim levels.
6-Speed Automatic (AC60F)
| Gear | Ratio |
|---|---|
| 1st | 3.333 |
| 2nd | 1.960 |
| 3rd | 1.353 |
| 4th | 1.000 |
| 5th | 0.728 |
| 6th | 0.588 |
| Reverse | 3.061 |
Available Axle Ratios
Toyota offered a few different axle ratios for the 2018 Tundra, tailored to different performance needs.
| Ratio | Available With | Axle Code | Best For |
|---|---|---|---|
| 4.10:1 | Standard on most 4.6L V8 models | B03A | Balanced Performance |
| 4.30:1 | Standard on 5.7L V8 models (especially with Tow Package) | B04A | Towing |
How to Identify Your Axle Ratio
For Toyota vehicles like the Tundra, the easiest way to find your axle ratio is by checking the manufacturer's sticker on the driver-side door jamb. Look for the "A/TM" (Axle/Transmission) code. The axle code is the four-character code starting with a letter.
- A/TM: B03A/AC60F translates to a 4.10:1 axle ratio.
- A/TM: B04A/AC60F translates to a 4.30:1 axle ratio.
You can also use a VIN decoder tool or, if you're comfortable getting under the truck, look for a tag or stamping on the differential housing itself, though the door jamb sticker is the most reliable method.
Towing vs. MPG Impact
The relationship between axle ratios, towing, and fuel economy is a classic trade-off:
-
Numerically Higher Ratios (e.g., 4.30:1): These are known as "shorter" gears. They provide more torque to the wheels, which is excellent for towing heavy loads, acceleration, and off-the-line performance. The engine will rev higher at any given speed, which leads to lower fuel economy.
-
Numerically Lower Ratios (e.g., 4.10:1): These are "taller" gears. They don't offer the same raw pulling power as a shorter gear, but they allow the engine to turn at a lower RPM on the highway. This results in better fuel efficiency at cruising speeds.
For the 2018 Tundra, the 4.30:1 ratio is the clear choice for those who frequently tow heavy trailers, while the 4.10:1 provides a more balanced approach for daily driving.
Common Issues
While the Tundra's powertrain is known for its durability, some owners have noted a whine or humming noise from the rear differential over time. This can sometimes be attributed to normal wear on the ring and pinion gears or, in some cases, wear in the carrier bearings. If you notice a new, persistent noise from the rear of your truck that changes with speed, it's wise to have it inspected.
More specs for the 2018 Toyota Tundra
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
Battery Size & Group
Group size, CCA, AGM/flooded, dimensions, reset note.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Fuse Box Diagram & Amperage
Fuse box locations, layout, amps, and what each fuse controls.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
Maintenance & repair guides
2018 Toyota Tundra Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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