Quick Facts

  • Manufacturer: Cummins Drivetrain and Braking Systems, formerly Meritor
  • Product Brand: Meritor XTended Lube
  • Product Series: MXL
  • Product Type: Extended-lubrication commercial-vehicle driveline family
  • Available Models: 155N, 16MXL, 17MXL, 176MXL, and 18MXL
  • Published Driveline Ratings: 3,800 to 16,500 lb-ft, depending on model
  • Published Metric Ratings: 5,152 to 22,371 N·m, depending on model
  • Lubrication Interval: Up to 100,000 miles under approved operating and maintenance conditions
  • Universal-Joint Design: Greaseable extended-lubrication universal joint
  • Primary Applications: Linehaul tractors, city-delivery trucks, buses, construction vehicles, fire apparatus, heavy-haul trucks, and specialized commercial equipment
  • Production Status: Current product family with application-specific assemblies and replacement components

Overview

The Meritor XTended Lube MXL Driveline is a family of commercial-vehicle driveshaft systems engineered to provide extended lubrication intervals while transferring power from the transmission to the drive axle.

The MXL family includes several sizes covering medium-duty and heavy-duty torque requirements. Published models range from the 3,800 lb-ft 155N to the 16,500 lb-ft 18MXL.

MXL drivelines use improved nitrile seals, triple-lip sealing, protective metal shrouds, high-strength tubing, and robust bearing retention. They retain grease fittings but can provide lubrication intervals of up to 100,000 miles when operated and maintained under approved conditions.

Key Characteristics

  • Extended-lubrication driveline family
  • Lubrication intervals of up to 100,000 miles
  • Multiple models for different torque requirements
  • High-strength steel tubing
  • Improved nitrile universal-joint seals
  • Triple-lip sealing system
  • Protective metal bearing shroud
  • Robust bearing-cap retention system
  • Strong clamping force helps prevent spinning bearing cups
  • Polyglide nylon-coated slip components
  • Compatible with industry-standard yokes
  • Designed for linehaul and city-delivery applications
  • Suitable for OEM installation and aftermarket conversion

Major Components

  • High-strength driveshaft tubing
  • MXL universal-joint assemblies
  • Universal-joint crosses
  • Bearing cups
  • Nitrile seals
  • Triple-lip sealing components
  • Protective metal shrouds
  • Bearing-retention hardware
  • Flange yokes
  • End yokes
  • Weld yokes
  • Slip yoke or slip assembly
  • Polyglide-coated splines
  • Companion flanges
  • Center bearing on applicable multi-piece systems
  • Center-bearing mounting bracket
  • Grease fittings
  • Balance weights

Product Type and Construction

The MXL is a tubular steel driveshaft family using greaseable extended-lubrication universal joints. Precision tubing, forged or machined yokes, splined slip components, bearings, seals, protective shrouds, and attachment hardware create the rotating assembly.

Complete MXL drivelines are application-specific. Model, shaft length, tubing dimensions, yoke design, flange pattern, spline configuration, slip travel, and center-bearing requirements vary by vehicle.

How the Driveline or Steering Component Works

The MXL receives rotational power through the transmission output connection and transfers it through the driveshaft to the drive axle. Universal joints allow the shaft to rotate while its connected components operate at different heights or angles.

The slip section accommodates changes in driveline length caused by suspension movement and chassis flex. Polyglide nylon coating reduces friction and helps limit axial loads within the slip section.

Position and Function Within the Vehicle

The MXL is installed beneath the vehicle between the transmission and the driven axle. Long-wheelbase trucks may use one or more shaft sections supported by a center bearing.

Its function is to transfer torque while accommodating suspension travel, chassis deflection, driveline-angle changes, and controlled axial movement between powertrain components.

Common Specifications

  • 155N Tubing: 4.00-inch outside diameter with a 0.080-inch wall
  • 155N Rating: 3,800 lb-ft or 5,152 N·m
  • 16MXL Tubing: 4.00-inch outside diameter with a 0.110-inch wall
  • 16MXL Rating: 6,000 lb-ft or 8,135 N·m
  • 17MXL Tubing: 4.095-inch outside diameter with a 0.180-inch wall
  • 17MXL Rating: 10,000 lb-ft or 13,558 N·m
  • 176MXL Tubing: 4.095-inch outside diameter with a 0.180-inch wall
  • 176MXL Rating: 12,000 lb-ft or 16,270 N·m
  • 18MXL Tubing: 4.59-inch outside diameter with a 0.180-inch wall
  • 18MXL Rating: 16,500 lb-ft or 22,371 N·m
  • Lubrication Interval: Up to 100,000 miles under approved service conditions
  • Seal Type: Improved nitrile triple-lip seal with protective metal shroud
  • Slip-System Treatment: Polyglide nylon coating

Exact specifications must be confirmed using the MXL model, complete driveline assembly number, vehicle identification number, engineering drawing, and connection dimensions.

Operating Capacity and Performance

The MXL family covers published driveline ratings from 3,800 to 16,500 lb-ft. The correct series must be selected according to engine torque, transmission ratios, axle gearing, shaft speed, vehicle weight, working angles, and operating duty.

Published ratings apply to correctly configured driveline systems. Low transmission gears can multiply engine torque significantly before that torque reaches the driveshaft.

Installation Position and System Function

An MXL driveline may serve as a main driveshaft, intermediate shaft, interaxle shaft, or one section of a multi-piece driveline. The position depends on the powertrain layout, wheelbase, axle arrangement, and required shaft length.

Installation must preserve correct phasing, slip travel, working angles, component clearance, center-bearing location, and critical-speed capability.

Torque Transfer or Steering-Assist Function

The MXL is a torque-transfer component and does not provide steering assistance. Rotational force passes through its yokes, universal joints, splines, tubing, and flange connections before reaching the drive axle.

Driveline Geometry and Operating Angles

Correct driveline geometry is essential for smooth operation. Transmission, shaft, center-bearing, interaxle, and axle-pinion angles must allow the universal joints to operate within their approved range.

Excessive or unequal working angles can cause vibration, accelerated joint wear, heat, seal damage, spline loading, and shaft fatigue.

Steering Geometry and Movement

Steering geometry does not directly control the MXL driveline. Frame movement, axle articulation, suspension changes, and chassis modifications can nevertheless alter its operating angles and clearance from nearby steering components.

Slip, Articulation, and Operating Travel

The universal joints provide angular articulation, while the splined slip section accommodates changes in driveline length. The Polyglide coating reduces spline friction and helps minimize axial loads.

Insufficient spline engagement can weaken the connection. A slip assembly that bottoms out can transmit damaging thrust loads into the transmission, center bearing, or axle.

Bearings, Joints, Shafts, Gears, and Structural Design

The MXL combines high-strength tubing, forged or machined yokes, splined components, universal-joint crosses, bearing cups, seals, protective shrouds, and retention hardware.

The robust bearing-retention system applies strong clamping force to help prevent bearing cups from spinning in the yoke. Multi-piece installations may also use a center bearing and structural mounting bracket.

Materials and Component Construction

MXL drivelines use high-strength steel tubing and forged or machined steel connection components. Consistent tube straightness supports driveline balance and high-speed operation.

Nitrile seals, triple sealing lips, protective metal shrouds, and nylon-coated splines help improve durability and contamination resistance.

Hydraulic and Electric Steering Assistance

Hydraulic and electric steering assistance are not part of the MXL driveline. Nearby steering shafts, hydraulic hoses, electrical harnesses, and assistance components must maintain adequate clearance from the rotating shaft.

Electronic Controls and Driver-Assistance Integration

The MXL is mechanically operated and does not require a dedicated electronic controller. Engine torque management, automated transmission programming, traction control, and stability-control systems can indirectly affect the loads applied to the driveline.

Speed, Torque, and Load Management

Driveline speed, working angle, and torque must remain within the limits approved for the exact MXL assembly. Long shafts may reach critical speed sooner than shorter shafts, while low transmission gears can create substantial torque multiplication.

Wheel hop, aggressive starts, abrupt clutch engagement, and sudden traction changes can expose the driveline to damaging shock loads.

Vibration, Balance, and Noise Control

An MXL assembly must remain dynamically balanced throughout its operating-speed range. Shaft straightness, balance weights, phasing, runout, universal-joint condition, flange alignment, and center-bearing position all affect vibration.

Dented tubing, missing balance weights, incorrectly phased components, or damaged flange pilots can produce vibration even when the universal joints appear serviceable.

Lubrication, Sealing, and Contamination Protection

MXL universal joints use grease fittings and an extended-lubrication design. Approved applications may permit lubrication intervals of up to 100,000 miles, but the correct interval depends on model, duty cycle, environment, and manufacturer requirements.

Improved nitrile triple-lip seals and protective metal shrouds help retain grease and protect the bearing cups from dirt, moisture, road salt, and physical damage.

Duty Cycle and Operating Conditions

The MXL supports linehaul, city delivery, construction, utility, heavy-haul, fire and rescue, bus, defense, and specialized commercial applications when properly specified.

Shorter lubrication intervals may be required for severe service involving water, mud, road salt, dust, off-road articulation, high-pressure washing, frequent stops, or sustained heavy loading.

Mounting and Installation

Installation requires the correct MXL series, shaft length, tubing, yokes, flange pattern, pilot diameter, fasteners, spline engagement, slip travel, and operating angles.

Flange faces must be clean and undamaged. Multi-piece installations also require correct center-bearing alignment, mounting position, support, and shaft phasing.

Alignment, Driveline, and Mounting Geometry

Alignment should be checked at the vehicle’s specified operating ride height. Engine mounts, transmission mounts, suspension height, center-bearing position, axle placement, and pinion angle can alter driveline geometry.

An MXL shaft should not be shortened, lengthened, welded, straightened, or rebalanced without approved commercial-driveline equipment and procedures.

Vehicle, Transmission, Axle, and Steering Compatibility

Compatibility depends on the MXL model, engine torque, transmission ratios, axle gearing, flange connections, wheelbase, suspension, shaft length, working angles, operating speed, and vehicle duty cycle.

The MXL designation alone does not confirm interchangeability. The complete assembly should be identified using the vehicle identification number, shaft number, engineering records, and measured connection dimensions.

Related Component and System Compatibility

MXL assemblies are compatible with industry-standard yokes when properly selected, supporting parts availability and aftermarket conversion. Every connection must still match the required series, dimensions, rating, and attachment method.

Replacement universal joints, slip yokes, end yokes, weld yokes, center bearings, tubing, and hardware must correspond to the exact MXL model and driveline assembly.

Common Applications

  • Linehaul tractors
  • Regional-haul trucks
  • City-delivery vehicles
  • Class 6 and Class 7 trucks
  • Class 8 trucks
  • Construction and utility vehicles
  • Fire and rescue apparatus
  • Heavy-haul equipment
  • Transit buses
  • Motor coaches
  • Mobile cranes
  • Material-handling vehicles
  • Rail-support equipment
  • Defense vehicles

Advantages

  • Lubrication intervals of up to 100,000 miles
  • Multiple ratings for medium- and heavy-duty applications
  • Reduced routine maintenance compared with conventional grease intervals
  • High-strength tubing with consistent straightness
  • Improved nitrile seal construction
  • Triple-lip contamination protection
  • Protective metal bearing shrouds
  • Strong bearing-cup retention
  • Polyglide coating reduces slip-section friction
  • Compatible with industry-standard yokes
  • Supports aftermarket conversion applications

Limitations or Considerations

  • MXL universal joints still require periodic lubrication
  • The maximum interval does not apply to every operating condition
  • Severe service may require more frequent lubrication
  • Each MXL model has a different torque rating
  • Complete assemblies are application-specific
  • Correct shaft length and connection dimensions are required
  • Improper working angles can cause vibration and wear
  • Dented or bent tubing can make the shaft unsafe
  • Suspension changes can alter driveline geometry
  • Commercial balancing equipment is required for shaft repairs
  • Higher-torque applications may require an RPL-series driveline

Driver and Operator Experience

A correctly installed MXL driveline should transfer power without noticeable vibration, clunking, shuddering, or speed-related noise. Drivers may first recognize a problem through floor vibration, a clunk during load changes, or shudder under acceleration.

New symptoms following suspension, transmission, axle, center-bearing, or driveline service should be investigated promptly.

Steering Feel and Driver Feedback

The MXL does not directly control steering feel. Severe driveline vibration can travel through the chassis and be felt through the steering column, cab floor, pedals, or driver’s seat.

Operating Speed, Angle, and Load Management

Fleets should verify that shaft speed, torque, working angles, gross vehicle weight, and duty cycle remain within the approved limits for the selected MXL model.

  • Avoid aggressive clutch engagement
  • Reduce wheel hop and sudden traction changes
  • Avoid unnecessary shock loading
  • Investigate vibration before continued high-speed operation
  • Recheck driveline geometry after suspension changes
  • Maintain adequate shaft and chassis clearance

Control Setup and System Calibration

The mechanical MXL driveline does not require electronic calibration. Engine torque limits, transmission programming, traction control, and powertrain-protection strategies can affect driveline loading and should remain correctly configured.

Inspection and Wear Points

  • Universal-joint seals
  • Protective metal shrouds
  • Cross-and-bearing assemblies
  • Bearing-cup retention hardware
  • Grease fittings
  • Flange and yoke connections
  • Driveshaft tubing
  • Balance weights
  • Slip splines and Polyglide coating
  • Slip-section seals
  • Center bearing and rubber support
  • Center-bearing mounting bracket
  • Transmission and axle connections
  • Clearance around the rotating shaft

Lubrication Requirements

MXL universal joints are greaseable and must be lubricated at the interval specified for the exact model and operating application. The published maximum interval is up to 100,000 miles.

Severe service involving water, mud, salt, dust, frequent washing, or high articulation may require shorter intervals. Lubricant should be applied using the manufacturer-approved type and procedure.

Component Service Life and Rebuildability

Service life depends on lubrication, torque, shaft speed, working angles, loading, contamination, corrosion, and installation quality. Universal joints, yokes, slip components, center bearings, and complete shafts may be serviced or replaced using approved components.

Shaft, Joint, Bearing, Gear, and Linkage Service Life

The shaft can provide extended service when it remains straight, balanced, correctly phased, and free from impact damage. Joint life decreases when lubrication is missed, seals are damaged, operating angles are excessive, or shock loading exceeds the approved conditions.

Seal, Hose, Sensor, and Electronic Service Life

The nitrile triple-lip seals and metal shrouds are essential to grease retention and contamination protection. The MXL does not contain hydraulic hoses, electronic sensors, or a dedicated electronic controller.

Maintenance and Ownership Notes

The MXL reduces lubrication frequency but remains a serviceable driveline. Fleets should document lubrication intervals and adjust them for severe operating conditions.

  • Lubricate universal joints at the required interval
  • Check that grease reaches all bearing cups
  • Inspect seals and protective shrouds
  • Check universal joints for looseness or binding
  • Inspect tubing for dents, cracks, or corrosion
  • Check flange bolts and attachment hardware
  • Confirm that balance weights remain attached
  • Inspect slip components and spline engagement
  • Check center bearings and brackets when equipped
  • Preserve shaft phasing during disassembly
  • Investigate vibration or clunking promptly

Common Driveline and Steering Problems

  • Speed-related vibration: Shaft imbalance, excessive runout, incorrect phasing, missing balance weights, or damaged tubing may cause vibration that changes with vehicle speed.
  • Acceleration shudder: Incorrect working angles, worn universal joints, loose mounts, axle windup, or improper ride height may cause vibration under torque.
  • Dry universal joint: Missed lubrication, blocked grease passages, damaged fittings, or incomplete grease distribution can cause bearing wear.
  • Contaminated joint: Damaged seals or shrouds can allow water and road debris to enter the bearing cups.
  • Spinning bearing cup: Loose or damaged retention hardware can allow movement between the bearing cup and yoke.
  • Slip-section binding: Corrosion, contamination, damaged splines, or incorrect assembly can prevent normal axial movement.
  • Center-bearing failure: Misalignment, imbalance, damaged brackets, or deteriorated rubber supports can damage the bearing.
  • Tube damage: Road debris, chassis contact, improper lifting, or collision damage can bend or dent the shaft.

Safety and Service Precautions

A disconnected or damaged driveshaft can move unexpectedly and cause serious injury. Secure the vehicle against movement and support the shaft before removing mounting hardware.

  • Do not work beneath an unsupported vehicle
  • Prevent the vehicle from rolling
  • Support the shaft before disconnecting it
  • Mark orientation and phasing before disassembly
  • Use approved fasteners and tightening procedures
  • Use the approved lubricant and service method
  • Do not weld or modify the shaft without approved procedures
  • Replace cracked or severely damaged components
  • Verify clearances before returning the vehicle to service

Identification Information

Identification may be found on a shaft label, stamped component, universal-joint kit, yoke, flange, parts record, or vehicle build sheet.

  • Vehicle identification number
  • Vehicle manufacturer and model
  • Complete driveline assembly number
  • Meritor or Cummins component number
  • MXL series and model
  • Installed shaft length
  • Tubing diameter and wall thickness
  • Flange or end-yoke dimensions
  • Spline diameter and count
  • Slip travel
  • Universal-joint kit number
  • Center-bearing number when equipped
  • Transmission and axle models

Buying Considerations

  • Identify the exact MXL model
  • Record the original driveline assembly number
  • Verify the required torque rating
  • Match the tubing specification
  • Match transmission and axle connections
  • Confirm pilot and fastener dimensions
  • Measure shaft length using the approved method
  • Verify slip travel and spline engagement
  • Check working angles and critical-speed requirements
  • Determine whether a center bearing is required
  • Confirm the intended lubrication interval
  • Evaluate the vehicle’s duty cycle and operating environment
  • Use a qualified commercial driveline supplier

Variants and Configurations

  • 155N driveline
  • 16MXL driveline
  • 17MXL driveline
  • 176MXL driveline
  • 18MXL driveline
  • Single-piece driveshaft
  • Multi-piece driveline
  • Interaxle driveline
  • Different shaft lengths
  • Different tubing dimensions
  • Different yoke and flange connections
  • Application-specific slip assemblies
  • Center-bearing installations
  • OEM and aftermarket configurations

Comparison to Similar Equipment

Compared with the Meritor Permalube RPL Series Driveline, the MXL uses greaseable extended-lubrication universal joints. The RPL family uses permanently lubricated and sealed universal joints.

Compared with the Meritor Permalube RPL20 Driveline, the 176MXL shares a 12,000 lb-ft published rating but uses a different universal-joint and lubrication design.

Compared with the Meritor Permalube RPL25 Driveline, the 18MXL has a slightly lower published rating and requires periodic lubrication.

Compared with the Dana Spicer Life Series Commercial Driveshaft, the MXL uses Meritor’s extended-lubrication sealing, bearing retention, and slip-system designs.

Best Fit For

  • Vehicles originally equipped with an MXL driveline
  • Fleets seeking extended lubrication intervals
  • Linehaul tractors
  • Regional-haul trucks
  • City-delivery vehicles
  • Medium-duty commercial trucks
  • Heavy-duty commercial trucks
  • Buses and motor coaches
  • Construction and utility vehicles
  • Applications benefiting from industry-standard yoke compatibility

Related Vehicle and Trailer Types

Related Truck and Trailer Models

Related Driveline and Steering System Types

Related Driveline and Steering Products

Related Equipment Systems

Related Guides

Regulatory and Compliance Notes

The driveline must remain appropriate for the vehicle’s certified configuration and must not interfere with brakes, steering, suspension, fuel systems, air lines, electrical equipment, exhaust components, or required ground clearance.

Powertrain, wheelbase, frame, suspension, axle, or tire modifications should preserve safe working angles, spline engagement, shaft containment, and component clearance.

Real World Operating Notes

The maximum 100,000-mile lubrication interval should not be treated as universal. Severe service, contamination, water exposure, or manufacturer-specific requirements may require substantially shorter intervals.

Technicians should confirm that fresh grease reaches every bearing cup. Grease appearing at only one seal does not necessarily confirm that the complete universal joint has been lubricated.

Driveline vibration should be diagnosed as a complete system because tires, wheels, mounts, suspension height, axle alignment, shaft balance, working angles, and center-bearing position can produce similar symptoms.

Frequently Asked Questions

What is the Meritor XTended Lube MXL Driveline?

It is a family of commercial-vehicle driveshaft systems designed with extended universal-joint lubrication intervals.

Which models are included in the MXL family?

Published models include the 155N, 16MXL, 17MXL, 176MXL, and 18MXL.

What is the maximum MXL driveline rating?

The 18MXL has the highest published rating in the listed MXL family at 16,500 lb-ft, or 22,371 N·m.

Are MXL universal joints permanently lubricated?

No. MXL universal joints are greaseable extended-lubrication components. Permalube RPL universal joints are the permanently lubricated Meritor design.

How often should an MXL driveline be lubricated?

Approved applications may allow intervals of up to 100,000 miles. The actual interval must follow the requirements for the exact model, vehicle, duty cycle, and operating environment.

What does the protective metal shroud do?

It helps protect the universal-joint seals and bearing area from road contaminants and physical damage.

Can an MXL replace a conventional Meritor driveline?

Some MXL products support aftermarket conversion and compatibility with industry-standard yokes. The series, dimensions, rating, shaft length, and connections must still be verified.

What causes an MXL driveline to vibrate?

Possible causes include incorrect working angles, imbalance, excessive runout, damaged tubing, missing balance weights, improper phasing, worn joints, loose connections, or center-bearing misalignment.

Are all MXL parts interchangeable?

No. Parts differ among the 155N, 16MXL, 17MXL, 176MXL, and 18MXL models and among application-specific assemblies.

How should the correct replacement driveline be identified?

Use the vehicle identification number, MXL model, original shaft assembly number, transmission and axle information, shaft length, tubing dimensions, and connection specifications.

Availability and Where to Find

Meritor XTended Lube MXL complete drivelines and service components may be available through Cummins and Meritor distributors, commercial-truck dealers, driveline specialists, fleet-maintenance suppliers, and heavy-duty parts providers.

Availability depends on the MXL model, complete assembly number, shaft dimensions, yoke and flange arrangement, universal-joint requirements, transmission, axle, and vehicle application.

Current product specifications are available through the Cummins Meritor XTended Lube MXL Driveline page. Application-specific service components may also be identified through Meritor Parts Xpress.

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