GM Firebird 1967-1981 Repair Guide

Detent Switch

Print

ADJUSTMENT



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Detent switch adjustment for 1968-72 THM 400 transmissions

Turbo Hydra-Matic 400 transmissions are equipped with an electrical detent, or downshift switch operated by the throttle linkage.

1968 Models

  1. Place the carburetor lever in the wide open position.
  2.  
  3. Position the automatic choke so that it is off.
  4.  
  5. Fully depress the switch plunger.
  6.  
  7. Adjust the switch mounting to obtain a distance of 0.05 in. between the switch plunger and the throttle lever paddle.
  8.  

1969-81 Models

  1. Pull the detent switch driver rearward until the hole in the switch body aligns with the hole in the driver. Insert a 0.092 in. diameter pin through the aligned holes to hold the driver in position.
  2.  
  3. Loosen the mounting bolt.
  4.  
  5. Press the switch plunger as far forward as possible. This will preset the switch for adjustment, which will occur on the first application of wide open throttle.
  6.  
  7. Tighten the mounting bolt and remove the pin.
  8.  

 
label.common.footer.alt.autozoneLogo