GM Full Size Vans 1967-1986 Repair Guide

Adjustments

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SHIFT LINKAGE



Powerglide Transmission

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the Powerglide shift linkage adjustment

  1. Loosen the shift rod adjusting nut at the bottom of the steering column. Set the transmission lever in Drive (D). Determine Drive by shifting the lever all the way to the right to the Low (L) detent. Rotate it back to the left, one detent, to Drive (D).
  2.  
  3. Attach the control rod to the lever and inner lever of the shaft assembly with the retainers.
  4.  
  5. Assembly the swivel, clamp, grommet, bushing, washers, and nut loosely on the selector lever.
  6.  
  7. Attach the control rod to the outer lever of the shaft assembly with the retainer.
  8.  
  9. Place the selector lever tang in Neutral drive gate of the selector plate assembly and insert the control rod into the swivel.
  10.  
  11. Rotate the lever at the bottom of the column clockwise viewed looking down the steering column, until the tang contacts the Drive side of the Neutral/Drive gate.
  12.  
  13. Tighten the nut.
  14.  

Turbo Hydra-Matic Transmissions
MODELS THROUGH 1976

See Figure 2

Click image to see an enlarged view

Fig. Fig. 2: Turbo Hydra-Matic shift linkage adjustment- models through 1976

  1. Lift the selector lever toward the steering wheel and allow the selector lever to be positioned in Drive by the detent. Do not use the selector lever pointer as a reference.
  2.  
  3. Release the selector lever. The lever should not be able to go into Low unless the lever is lifted.
  4.  
  5. Lift the selector lever toward the steering wheel and allow the lever to be positioned in Neutral by the transmission detent.
  6.  
  7. Release the selector lever. The lever should not be able to engage reverse unless the lever is lifted. A properly adjusted linkage will prevent the lever from moving beyond both the Neutral and Drive detents unless the lever is lifted.
  8.  
  9. If adjustment is required, remove the screw and spring washer from the swivel clamp
  10.  
  11. Set the transmission lever in Neutral by moving it counterclockwise to 1 and then 3 detents clockwise.
  12.  
  13. Put the transmission selector lever in Neutral as determined by the mechanical stop in the steering column.
  14.  
  15. Assembly the swivel spring and washer to the lever and tighten.
  16.  
  17. Readjust the Neutral safety switch if necessary.
  18.  
  19. If the indicator pointer fails to line up properly with the gear symbol, adjust the position of the pointer and scale.
  20.  

1977-81 MODELS

See Figure 3

Click image to see an enlarged view

Fig. Fig. 3: Turbo Hydra-Matic shift linkage adjustment-1977-81 models

Perform the procedure exactly and in the order presented. Failure to do so may lead to premature transmission failure due to operation without the controls in the full detent position. Such operation will result in reduced oil pressure, and therefore only partial engagement of the drive clutches. Partial engagement of the clutches with sufficient pressure to cause apparent normal operation will result in transmission failure after only a few miles of operation.

  1. Remove the nut (F) and slide off the washers, grommet, bushing and clamp (E). Remove swivel (D).
  2.  
  3. Remove the retainer, grommets and the transmission lever (C) from the shaft assembly.
  4.  
  5. Set the transmission lever (C) in the Neutral position either by moving the lever (C) counterclockwise to the L1 position, then clockwise 3 steps to the Neutral position, or by moving the lever (C) clockwise to the Park position, then counterclockwise 2 steps to the Neutral position.
  6.  
  7. Set the column shift lever in the Neutral position by rotating the shift lever until it locks into the stop in the column. Do not use the gear select pointer as a reference to position the column shift lever.
  8.  
  9. Attach rod (A) to the shaft assembly (B) as shown.
  10.  
  11. Slide the swivel (D) and the clamp (E) onto rod (A). Align the column shift lever and loosely attach the assembly.
  12.  
  13. Hold the column shift lever against the Neutral stop, on the Park position side.
  14.  
  15. Tighten the nut (F) to 18 ft. lbs. (24 Nm).
  16.  
  17. Adjust the indicator needle if necessary. It may also be necessary to adjust the neutral start switch.
  18.  

1982 AND LATER MODELS

See Figure 4

Click image to see an enlarged view

Fig. Fig. 4: Turbo Hydra-Matic shift linkage adjustment-1982 and later models, column shift shown

  1. Set the trans lever (A) in the neutral position by moving it clockwise to the P detent, then counterclockwise 2 dents to N .
  2.  
  3. Set the column shift lever to the N gate notch, by rotating it until the shift lever drops into the N gate. Do not use the indicator pointer as a reference to position the shift lever, as this will not be accurate.
  4.  
  5. Attach rod (C) to the transmission shaft assembly as shown.
  6.  
  7. Slide the swivel and clamp onto rod (C) and align it with the column shift lever. Complete the attachment.
  8.  
  9. Hold the column lever against the N stop on the P position side. Tighten the nut.
  10.  

LOW BAND

Only the Powerglide transmission has bands requiring adjustment; the Turbo Hydra-Matic uses non-adjustable clutches.

  1. Raise and support the vehicle.
  2.  
  3. Place the selector lever in Neutral.
  4.  
  5. Remove the protective cap from the low band adjusting screw on the left side of the transmission.
  6.  
  7. Loosen the adjusting screw locknut 1 / 4 turn and hold it in this position with a wrench.
  8.  
  9. Using an in.lb. torque wrench, adjust the band adjusting screw to 70 in. lbs. (7 Nm), and back the screw off 4 complete turns for a band that has been in operation more than 6000 miles (9654 km), or 3 complete turns for a band that has been in operation less than 6,000 miles.
  10.  

The back-off figure is not approximate; it must be exact.

  1. Tighten the adjusting screw locknut.
  2.  
  3. Lower the vehicle and road test.
  4.  

 
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