GM Firebird 1967-1981 Repair Guide

Detent Cable


ADJUSTMENT Turbo Hydra-Matic 250, 350 Models

See Figure 1

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Fig. Fig. 1: Detent cable adjustment for THM 350 transmissions THM 250 transmissions similar

These transmissions utilize a downshift cable between the carburetor and the transmission.

  1. Pry up on each side of the detent cable snaplock with a prytool to release the lock. On cars equipped with a retaining screw, loosen the detent cable screw.
  3. Squeeze the locking tabs and disconnect the snaplock assembly from the throttle bracket.
  5. Place the carburetor lever in the wide open throttle position. Make sure that the lever is against the wide open stop. On cars with Quadrajet carburetors, disengage the secondary lock-out before placing the lever in the wide open position.

The detent cable must be pulled through the detent position.

  1. With the carburetor lever in the wide open position, push the snaplock on the cable or else tighten the retaining screw.

Do not lubricate the detent cable.