2025-2026 Catalog [Effective Fall 2025] 
    
    May 29, 2025  
2025-2026 Catalog [Effective Fall 2025]

HET 119 Mechanical Transmissions

Lecture: 2 Lab: 2 Clinic: 0 Credits: 3
This course introduces the operating principles of mechanical medium and heavy duty truck transmissions. Topics include multiple counter shafts, power take-offs, sliding idler clutches, and friction clutches. Upon completion, students should be able to diagnose, inspect, and repair mechanical transmissions.

Pre-requisite(s): TRN 110  
Course is typically offered in Summer.
Student Learning Outcomes (SLOs)
At the completion of the course, the student will be able to according to NATEF:

  1. Categorize the types and use of gears and components in truck transmissions, including input/output shafts, main and countershaft gears, PTOs, and transfer cases.
  2. Calculate gear pitch to determine gear ratios while tracing the power flow from input to output across various gear arrangements.
  3. Define the relationship between speed and torque in different gear configurations.
  4. Outline the functions of main and auxiliary gear sections in a typical twin countershaft transmission.
  5. Assemble components following disassembly and inspection of a transmission.