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Shift Speed Test

  1. Connect scan tool and observe throttle angle and vehicle speed at shift points. Operate vehicle in Overdrive. Accelerate using steady throttle pressure. Note shift points for 2nd, 3rd, Overdrive and TCC application. TCC application should occur in 3rd or Overdrive.
  2. Torque converter clutch will not engage until engine coolant has reached a temperature of 140°F (60°C). Compare shift points to shift speed charts. See Fig 1-4.
  3. Operate vehicle in Overdrive normally at 40-55 MPH with throttle in half-open position. Ensure TCC releases, and note 3rd gear downshift point. Repeat procedure with wide open throttle. Ensure TCC releases, and note 2nd gear downshift point.
  4. Operate vehicle normally in Overdrive, at 40-55 MPH. Release accelerator while manually shifting transmission to 3rd gear. Ensure TCC releases and engine braking is felt, and note 3rd gear downshift point.
  5. Operate vehicle normally in Overdrive, at 40-45 MPH. Release accelerator while manually shifting transmission into 2nd gear. Ensure TCC releases and engine braking is felt, and note 2nd gear downshift point.
  6. With transmission in Overdrive, accelerate normally to 25 MPH, allowing vehicle to upshift normally. Release accelerator while manually shifting transmission into 1st gear. Ensure TCC releases and engine braking is felt, and note 1st gear downshift point.
  7. With transmission in Overdrive, accelerate to 4th gear with TCC applied. Release accelerator. Lightly apply brakes, and ensure TCC releases and note speed at which downshifts occur. Compare shift points noted to shift speed charts. See Fig 1-4.
  8. Place transmission in 3rd gear with vehicle stopped. Accelerate, and note 1st-2nd and 2nd-3rd shift points. Repeat procedure with transmission in 2nd gear. Note 1st-2nd shift point. Accelerate to 25 MPH. Ensure 2nd-3rd gear upshift does not occur and TCC does not engage.
  9. Place transmission in 1st gear with vehicle stopped. Accelerateto 20 MPH. Ensure upshifts do not occur and TCC does not engage. With vehicle stopped, place transmission in Reverse and slowly accelerate to observe reverse gear operation.
  10. Compare all shift points to shift speed charts. See Fig 1-4. If shift points are not within speed listed, see TROUBLE SHOOTING. Control pressure can also be checked. See CONTROL PRESSURE TEST.
Fig 1: Shift Speed Chart (1993 - All Models)
G94J36722Courtesy of GENERAL MOTORS CORP.
Fig 2: Shift Speed Chart (1994 Passenger Vehicles)
G94A36723Courtesy of GENERAL MOTORS CORP.
Fig 3: Shift Speed Chart (1994 Light Trucks & Vans)
G94B36724Courtesy of GENERAL MOTORS CORP.
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