The PACCAR TX-18 is an 18-speed transmission designed for heavy-duty vehicle applications. This operator's manual provides comprehensive information on its features, operation, and maintenance, ensuring safe and efficient use.

Function Description:

The PACCAR TX-18 transmission is an automated manual transmission (AMT) that offers 18 forward speeds and multiple reverse gears, including high-range reverse gears (R4-R6) for specific applications. It is designed to optimize vehicle performance, fuel economy, and driver comfort through various intelligent features. The transmission can be operated in automatic or manual modes, allowing the driver to select gears or rely on the system's optimized gear selection. It integrates with other vehicle systems like cruise control and engine braking to provide a cohesive driving experience.

Important Technical Specifications:

Gear Speeds: 18 forward speeds, R1-R3 standard reverse, R4-R6 high-range reverse (PRO only).
Lubricant Capacity: 25.4 US pints (approximately 12 liters).
Air System Pressure Range: Maintain between 90 psi (5.9 bar) and 130 psi (9.0 bar) for proper operation.
Transmission Oil Temperature: Monitored by a gauge, with a normal operating range. Overheating can lead to Clutch Abuse Protection activation.
Clutch Temperature: Monitored by a gauge, with states indicating normal, elevated (white glow), and overheated (red glow) conditions.
Fastener Torque Requirements: Detailed specifications for frame fasteners, including standard grade 8 UNF/UNC nylon lock-nuts and all-metal lock-nuts, with specific torque values in lb-ft and N·m. For example, a 1-1/8 inch standard fastener with nylon insert nuts requires 990-1,170 lb-ft (1,346-1,591 N·m).

Usage Features:

Column Shifter: Located on the right-hand side of the steering column, it allows the operator to switch transmission modes (Drive, Neutral, Reverse), upshift/downshift, and activate Manual, Hold, Low, and MAX modes.
Auto-neutral: Automatically shifts the transmission into Neutral if left in a forward or reverse mode with the parking brake set.
Clutch Abuse Protection: Activates if clutch temperature is elevated or overheating, limiting launch gears, disabling Urge to Move and Creep Mode, and potentially preventing clutch engagement to allow cooling.
Coast Mode: Shifts the transmission into neutral when coasting to a stop, providing a smooth stopping experience. The default Coast Down Gear is 7th, but this can be adjusted.
Creep Mode: Allows the vehicle to be driven at a constant speed at engine idle without pressing the accelerator pedal, useful for slow-speed applications.
Cruise Control Compatibility: The transmission system is compatible with cruise control, with functions and features varying by engine. A 'rationality check' ensures service brakes are working before cruise control activation.
Engine Underspeed Protection: Downshifts the transmission to prevent engine lugging and potential stalls during low RPM conditions in Drive or Manual mode.
Engine Overspeed Protection: Upshifts the transmission to prevent engine overspeed in Drive, Manual, and Low modes.
High-range Reverse (PRO only): Supports operation in three high-range reverse gears (R4-R6) for higher reverse operating speeds.
Hill Start Aid (HSA): Prevents unwanted vehicle movement on steep grades when transitioning from the brake to the throttle. Can be disabled via a switch.
Hold Gear Mode (option): Replaces Manual mode, allowing the operator to select a specific gear and maintain it.
Load-based Shifting: Adjusts the transmission shift schedule based on vehicle weight, road grade, engine RPM, and accelerator pedal position for improved fuel economy and performance.
Low Mode: Restricts the transmission to first gear, providing additional torque. Useful for stopping heavy loads with engine braking and maintaining power on steep grades at low speeds.
MAX Mode: Applies 100% engine braking and uses lower transmission gears to quickly slow the vehicle without relying on service brakes.
Neutral Coast Mode: Places the transmission into Neutral on slight downhill grades to improve fuel economy when cruise control is active and the transmission is in Drive.
Optimized Gear Selection: Automatically selects the start gear based on vehicle weight, road grade, and axle/transmission ratio.
Transmission Power Take-off (PTO) (option): Supports both mobile (1st-5th and R1-R3 gears) and stationary PTO operation.
Urge to Move: Automatically starts the vehicle at engine launch once a transmission mode is selected and service brakes are released, providing a constant speed at engine idle.

Maintenance Features:

Preventative Maintenance Schedule: Includes weekly checks, and checks at 7,500 mi / 12,000 km, 30,000 mi / 48,000 km, 60,000 mi / 96,000 km / 6 mo, annually, 240,000 mi / 384,000 km / 3 yr, and 500,000 mi / 800,000 km / 5 yr.
Weekly Checks: Inspect exterior for leaks, check oil level, and inspect oil filter and exterior seals.
Air Compressor Maintenance: Regular checks for air compressor, air dryer oil-coalescing cartridge, and air lines.
Cooling System Maintenance: Includes checks for coolant concentration (glycol level), coolant extender, coolant level, and coolant filter. Emphasizes using genuine PACCAR coolant filters and avoiding mixing different coolant formulations.
Lubrication: Detailed procedures for checking and adding transmission fluid, including specific oil temperature ranges for accurate checks.
Troubleshooting: Provides diagnostic steps for common issues, including engine not cranking, denied shifts, and transmission reset procedures.
Roadside Assistance: PACCAR Vehicle Support Center offers 24/7 assistance for various issues, including jump starts, towing, and mechanical repairs.

Paccar TX-18 - Page 21

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