GM Astro/Safari 1985-1996 Repair Guide

Adjustments

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SHIFT LINKAGE



See Figures 1, 2 and 3



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Fig. Fig. 1: Shifting positions-THM 700-R4 (4L60) models with 3-gear (forward) shift levers



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Fig. Fig. 2: Shifting positions-THM 700-R4 (4L60) and 4L60E models with 4-gear (forward) shift levers



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Fig. Fig. 3: Exploded view of the automatic transmission shift linkage-1985-94 models (1995 similar)

The 1985-95 vehicles covered by this guide that are equipped with automatic transmissions utilize a mechanical shift lever and linkage assembly. Starting in 1996, the shift linkage was replaced by a shift cable. For 1996 vehicles, please refer to the cable replacement and adjustment procedure found later in this section.

  1. Firmly apply the parking brake and block the rear wheels.
  2.  
  3. Raise and support the front of the vehicle on jackstands.
  4.  
  5. At the left side of the transmission, loosen the shift rod swivel-to-equalizer lever nut on 1985-89 vehicles or the bracket-to-frame screw on 1990-95 vehicles.
  6.  
  7. At the steering column, place the gear selector lever into the Neutral position.
  8.  

When positioning the gear selector lever, DO NOT use the steering column indicator to find the Neutral position, instead count gate positions from Park, through Reverse to the Neutral gate.

  1. Rotate the transmission shift lever counterclockwise (toward the front of the transmission) to the first (Park) position, then turn it clockwise (rearward) to the 2nd detent (Neutral) position. Remember that the first position and the first detent are not the same. The first position, or fully counterclockwise is Park, when you turn the lever clockwise 1 detent, the transmission will be in Reverse, then turn it to the second detent and it will be in Neutral.
  2.  
  3. Holding the rod tightly in the swivel, tighten the retainer which was loosened to allow the adjustment. For 1985-89 vehicles, you should have loosened the equalizer lever nut and it should be tightened to 11 ft. lbs. (14 Nm). For 1990-95 vehicles, the bracket-to-frame screw should be tightened to 21 ft. lbs. (28 Nm).
  4.  
  5. Place the gear selector lever (on the steering column) in the P position and check the adjustment. Move the gear selector lever into the various positions; the engine must start ONLY in the P and the N positions.
  6.  
  7. If the engine will not start in the N and/or P positions, refer to the Back-Up Light Switch adjustment information in Chassis Electrical and adjust the switch.
  8.  


CAUTION
With the gear selector lever in the PARK position, the parking pawl should engage the rear internal gear lugs or output ring gear lugs to prevent the vehicle from rolling and causing personal injury.

  1. Align the gear selector lever indicator, if necessary.
  2.  
  3. Remove the jackstands and carefully lower the vehicle
  4.  

THROTTLE VALVE (TV) CABLE



See Figure 4



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Fig. Fig. 4: Adjusting the TV cable-V-6 on left, L-4 at middle and close-up of the adjuster assembly at right

Only the THM 700-R4 (4L60) transmission (1985-92) utilizes a Throttle Valve (TV) and cable. Shift control on the 4L60-E is electronically controlled.

If the TV cable is broken, sticky, misadjusted or is the incorrect part for the model, the vehicle may exhibit various malfunctions, such as delayed or full throttle shifts.

Preliminary Checks
  1. Inspect and, if necessary, correct the transmission fluid level.
  2.  
  3. Make sure that the brakes are not dragging and that the engine is operating correctly.
  4.  
  5. Make sure that the cable is connected at both ends.
  6.  
  7. Make sure that the correct cable is installed.
  8.  

Adjustment
  1. Remove the engine cover in the passenger compartment for access to the throttle lever. For details on cover removal, please refer to General Information & Maintenance of this guide.
  2.  
  3. If necessary, remove the air cleaner.
  4.  
  5. If the cable has been removed and installed, check to see that the cable slider is in the zero or the fully adjusted position; if not, perform the following procedures:
    1. Depress and hold the readjust tab (located at the engine end of the TV cable).
    2.  
    3. Move the slider back through the fitting (away from the throttle lever) until it stops against the fitting.
    4.  
    5. Release the readjust tab.
    6.  

  6.  
  7. Rotate the throttle lever to the Full Throttle Stop position. Be sure to manually operate the throttle lever, DO NOT use the accelerator pedal. The slider will ratchet toward the lever as it is rotated, so listen for at least 1 click.
  8.  
  9. Release the throttle lever.
  10.  
  11. Verify that the cable moves freely. The cable may appear to function properly with a stopped and cold engine. Recheck after normal operating temperature has been reached.
  12.  
  13. If removed for access, install the air cleaner assembly.
  14.  
  15. Road test the vehicle and confirm proper operation.
  16.  
  17. Install the engine cover to the passenger compartment.
  18.  

 
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