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Road Test

  1. If vehicle is not so equipped, attach tachometer to engine. Check minimum throttle upshifts in "D" position. See MERKUR SHIFT SPEEDS TABLE  . Transmission should start in 1st gear, shift to 2nd, and then shift to 3rd gear as speed increases.
  2. With transmission in 3rd gear, depress accelerator through detent (to floor). Transmission should shift from 3rd to 2nd, or 3rd to 1st, depending on vehicle speed.
  3. Check closed throttle downshift from 3rd to 1st by coasting down from about 30 MPH in 3rd gear. Shift should occur at correct vehicle speed. With transmission selector lever in "2" position, transmission should operate only in 2nd gear.
  4. With transmission in 3rd gear and road speed over 50 MPH, transmission should downshift to 2nd gear when selector lever is moved from "D" to "2" or "1". When same manual shift is made below 25 MPH, transmission should shift from 2nd or 3rd to 1st.
  5. Step 1) will determine if governor pressure and shift control valves are operating properly. Erratic shifts could be caused by stuck governor valve. If shift points do not occur at correct engine RPM or road speeds, check linkage, engine operating condition, and vacuum supply.
    Fig 1: Cutaway View of C-3 Automatic Transmission Assembly
    G96A16063Courtesy of FORD MOTOR CO.
  6. Slipping (increase in engine speed greater than increase in road speed) in gear usually indicates clutch or band problems. Specific clutch or band that is slipping can usually be determined by noting transmission operation in each selector position. Compare application of internal components as used in those positions. See CLUTCH & BAND APPLICATION TABLE  .
MERKUR SHIFT SPEEDS

Shift MPH Output Shaft RPM
1-2 minimum 10-15 in. Hg. 12-16 580-790
2-3 minimum 10-15 in. Hg. 17-24 845-1215
1-2 to detent 6 psi boost pressure 35-41 1740-2060
2-3 to detent 6 psi boost pressure 50-56 2480-2800
1-2 thru detent (WOT) 10 psi boost pressure 41-47 2038-2325
2-3 thru detent (WOT) 10 psi boost pressure 65-71 3275-3560
3-2 torque demand lockout 1 psi boost pressure 33-39 1640-1955
3-2 thru detent (kickdown) max. lockout 5 psi boost pressure 57-63 2850-3170
3-1 or 2-1 thru detent (kickdown) max. lockout 3 psi boost pressure 28-36 1425-1795
3-2 closed throttle coast out 11-17 530-845
2-1 closed throttle coast out 8-15 425-740
2-1 manual low closed throttle coast out 30-41 1530-2060
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