A/T - 440T4 Lock Up And Cruise Control Problems

TSB 89-20 (June)

SUBJECT: Lock-up and cruise control problems

Hydra-matic 4T60/THM 440-T4




Some 440-T4 Transmissions use a vehicle speed sensor (VSS) in the governor cover. (See Figure) This is an electronic unit that is used instead of a "normal" gear driven speedometer.

DO NOT PLACE THE VSS IN THE PARTS WASHER!

We have received several calls on intermittent lock-up, erratic speedometer readings, and surging with the cruise control on.

These problems have been traced to VSS units that have been cleaned in a spray washer.