This article reviews the status of heavy-duty automotive transmissions in the United States. Design still is centered around three basic types of transmissions: mechanical, semi-automatic and automatic. In the present market, automatics have increased their share to 15%, but in the medium- and heavy-duty fields, 97% of the transmissions are mechanical. Semi-automatics dominate the off-highway field. The cost of automatics for heavy trucks, and the greater technical knowledge required to service them are limiting their application. However, their convenience, and increased productivity for lighter trucks are thought to hold promise of future extension to heavier vehicles. The Snapper semi-automatic produced by Eaton Corporation arranges a simple mechanism into the gearing to allow the operator to preselect the desired gear. Once the selection is made, the transmission automatically shifts itself. The mechanism that controls the engagement is mechanical logic responding to engine manipulation. All shifts reportedly are done at synchronous speeds without shock to the drive train.

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  • Corporate Authors:

    Automotive Industries International

    Chilton Way
    Radnor, PA  United States  19089
  • Authors:
    • Stark, J A
  • Publication Date: 1978-12

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00314836
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Jul 22 1980 12:00AM