Tracing Serial A36172 and the Legacy of Michigan Clark Wheel Loaders

[MikePhua]

The Michigan Clark Brand and Its Industrial Footprint
Michigan Clark was once a dominant name in the wheel loader industry, especially during the 1960s and 1970s. The company, originally Michigan Power Shovel, merged with Clark Equipment and became known for producing rugged, mechanically simple loaders that were widely used in quarries, municipal yards, and construction sites. Their machines were often identified by serial numbers stamped on the frame or transmission housing, with formats like A36172 indicating production batches, model variants, or factory origin.
Terminology annotation:

• Wheel loader: A heavy equipment machine used for loading materials into trucks, stockpiling, or grading, typically with a front-mounted bucket.
  
• Serial number: A unique identifier assigned to each machine during manufacturing, used for tracking production, parts compatibility, and service history.
  

Serial A36172 likely corresponds to a mid-1970s Michigan 75B or 75C loader, based on known production records and surviving units. These models were powered by Detroit Diesel 4-53 engines and featured Clark planetary axles and powershift transmissions.
Identifying the Machine Behind the Serial
Serial numbers like A36172 can be decoded using factory records, parts manuals, or dealer archives. While Clark Equipment’s original records are fragmented due to corporate transitions, many enthusiasts and rebuilders have compiled unofficial databases. Key identifiers include:

• Prefix letter (e.g., A) indicating model series or production plant
  
• Numeric sequence (e.g., 36172) denoting unit number within batch
  
• Casting codes on transmission and axle housings for cross-reference
  

In one restoration case in Kansas, a loader with serial A36172 was confirmed to be a Michigan 75C built in 1976, originally sold to a limestone quarry and later transferred to a county road department.
Terminology annotation:

• Casting code: A number or symbol molded into a metal part during manufacturing, used to identify production date or batch.
  
• Planetary axle: A gear system within the axle hub that multiplies torque and reduces stress on drivetrain components.
  

Engine and Drivetrain Configuration
Machines in the A36100–A36200 range typically featured:

• Detroit Diesel 4-53N or 4-53T engines (naturally aspirated or turbocharged)
  
• Clark 18000 series powershift transmission
  
• Clark 37Z planetary axles
  
• Torque converter with stall ratio around 2.5:1
  
• Hydraulic gear pump system with open-center valves
  

These components were known for durability but required regular maintenance, especially in dusty or high-load environments.
Maintenance recommendations:

• Change transmission fluid every 500 hours
  
• Inspect axle seals and planetary gear oil quarterly
  
• Replace hydraulic filters every 250 hours
  
• Monitor engine blow-by and adjust valve lash annually
  

Terminology annotation:

• Stall ratio: The torque multiplication factor provided by a torque converter when the output shaft is stalled.
  
• Blow-by: Combustion gases that escape past piston rings into the crankcase, indicating engine wear.
  

In a fleet in Alberta, a loader with serial A36172 ran over 18,000 hours before its first major engine overhaul, a testament to the resilience of the Detroit 4-53T.
Parts Sourcing and Restoration Challenges
With Clark Equipment no longer supporting these models directly, parts must be sourced through:

• Aftermarket suppliers for Detroit Diesel components
  
• Salvage yards specializing in vintage construction equipment
  
• Fabrication shops for bushings, pins, and sheet metal
  
• Rebuilt transmission and axle assemblies from specialty rebuilders
  

Common restoration issues include:

• Transmission clutch pack wear and seal leakage
  
• Axle planetary gear pitting
  
• Hydraulic valve spool scoring
  
• Cab instrumentation failure due to corrosion
  

Terminology annotation:

• Clutch pack: A set of friction discs and steel plates used in powershift transmissions to engage gears.
  
• Valve spool: The sliding component inside a hydraulic valve that directs flow based on position.
  

In one rebuild project in Oregon, a loader with serial A36172 was restored using parts from two donor machines and custom-fabricated transmission seals, returning to service for snow removal and gravel loading.
Historical Significance and Collector Interest
Michigan Clark loaders with serial numbers like A36172 are increasingly sought after by collectors and vintage equipment enthusiasts. Their mechanical simplicity, robust construction, and distinctive styling make them ideal candidates for restoration and display. Some have been retrofitted with modern LED lighting, upgraded seats, and digital hour meters while retaining original drivetrain components.
Suggestions for preservation:

• Document serial number and casting codes for future reference
  
• Maintain original paint scheme and decals if possible
  
• Replace wiring harness with marine-grade wire for reliability
  
• Add magnetic drain plugs to capture fine metal particles
  

Terminology annotation:

• Magnetic drain plug: A plug with an embedded magnet that attracts ferrous debris, aiding in system cleanliness.
  
• Marine-grade wire: Electrical wire designed for harsh environments, resistant to corrosion and vibration.
  

At a 2023 equipment show in Indiana, a restored Michigan 75C with serial A36172 won “Best Vintage Loader” after a full mechanical and cosmetic rebuild, drawing attention from both contractors and historians.
Conclusion
Serial A36172 is more than a number—it’s a gateway into the legacy of Michigan Clark wheel loaders and the industrial era they helped shape. Whether used in gravel pits, road departments, or private yards, these machines continue to serve and inspire. With careful documentation, resourceful parts sourcing, and mechanical dedication, loaders like the one behind A36172 can be preserved for generations to come.