Fuller RTLO18918AH

The Eaton Fuller RTLO-18918 series is a line of heavy-duty, 18-speed manual transmissions specifically engineered for high-performance commercial truck applications. These transmissions are part of the renowned Fuller Roadranger series, which has long been trusted in the trucking industry for its durability, efficiency, and operational flexibility. The RTLO-18918 family is especially suitable for Class 8 trucks operating in long-haul, heavy-haul, and vocational segments where power, control, and reliability are paramount.

General Overview

The RTLO-18918 series includes various revisions (such as RTLO-18918A, RTLO-18918B, etc.), all built with a common core design philosophy. These transmissions are constant mesh, twin countershaft, manual units offering 18 forward gears and 4 reverse gears. They feature an overdrive configuration, allowing for lower engine speeds at highway cruising speeds, which helps reduce fuel consumption and engine wear.

The “18” in the model number indicates the number of forward gears, while “189” refers to the torque capacity (1,850 lb-ft), and the “O” stands for overdrive. The “L” signifies that the transmission is equipped with an internal lubrication pump, which enhances oil circulation to critical components, particularly useful in severe-duty applications or during extended uphill driving.

Notable Features

• Overdrive Top Gear: The 0.73:1 overdrive gear reduces engine RPM at highway speeds, improving fuel efficiency and reducing engine wear.
• Lubrication Pump: The integrated pump ensures consistent lubrication to all components under high-stress or steep-grade operating conditions.
• Twin Countershaft Design: Balances engine torque across two shafts, improving durability and transmission longevity.
• Splitter and Range Functionality: Allows each gear position to be split into high and low for precise control across various speeds and load conditions.
• Double H-Pattern Shifter: Traditional manual shifter with a range selector and splitter button, allowing full access to all 18 gears.

Applications

The Fuller RTLO-18918 series is widely used across industries where high torque and versatility are essential, including:

• Long-haul freight and linehaul trucking
• Heavy haul and oversize load transport
• Logging and forestry trucks
• Tanker and bulk material hauling
• Oilfield and off-road vocational trucks
• Construction and specialized equipment transport

Summary

The Fuller RTLO-18918 manual transmission series stands as one of the most capable and versatile heavy-duty manual transmissions in the commercial trucking world. With 18 forward speeds, overdrive efficiency, a built-in lube pump, and a rugged twin-countershaft design, it delivers consistent performance and reliability under the toughest working conditions. Whether tackling steep mountain grades, carrying oversize loads, or cruising cross-country, the RTLO-18918 series provides the torque, gear flexibility, and fuel economy that professional drivers and fleet operators demand.

Technical Specifications:

• Model Series: RTLO-18918 (includes RTLO-18918A, RTLO-18918B, etc.)
• Type: Manual, 18-speed, constant mesh
• Speeds: 18 forward, 4 reverse
• Input Torque Rating: 1,850 lb-ft (2,508 Nm)
• Maximum Horsepower: Up to 550 HP (varies by application)
• Transmission Weight (dry): Approximately 714 lbs (324 kg)
• Lubrication System: Built-in oil pump (denoted by “L” in model name)
• Oil Capacity: 28 pints (13.2 liters)
• Recommended Lubricant: Eaton Roadranger-approved synthetic transmission fluid
• Input Shaft: 2.00-inch diameter, 10-spline
• Clutch Compatibility: Typically paired with 14-inch pull-type clutches
• Power Take-Off (PTO) Ports: Two (one on each side of the case)
• Case Material: Aluminum alloy (lightweight yet strong)

Gear Ratios

The RTLO-18918 series features a wide gear ratio spread that provides excellent low-speed torque multiplication for starting under load, as well as overdrive for efficient highway cruising.

Forward Gear Ratios (Approximate):

• 1st Gear: 14.40:1
• 2nd Gear: 12.54:1
• 3rd Gear: 10.47:1
• 4th Gear: 8.61:1
• 5th Gear: 7.06:1
• 6th Gear: 5.78:1
• 7th Gear: 4.76:1
• 8th Gear: 3.89:1
• 9th Gear (direct): 3.23:1
• 10th–16th Gears: Progressively lower ratios (from 2.73 to 1.00:1)
• 17th Gear: 0.86:1
• 18th Gear (Overdrive): 0.73:1

Reverse Gear Ratios:

• Low Reverse: 17.12:1
• High Reverse: 4.03:1

Call now to order!

800-621-3914