Transmission Switch

1972 GMC P25/P2500 Van 5.0L Eng VIN FSECTION Transmission Switch

Transmission mounted spark control switch is a two-way switch actuated by shifter shaft on manual transmissions, and by oil pressure on automatic transmissions. In low gear(s) points are closed. In high gear points open, breaking circuit to reversing relay and permitting vacuum to distributor advance unit.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.