HI - I have a 1993 6.5 TD


I am having a problem with the torque converter locking and unlocking.


It started out as just an occasional thing when I hit a bump but it got worse untill now when the engine comes up to temperature it stays unlocked most of the time.


is their a relay or loose connection that has been a problem?


Does anyone have a wiring diagram for this system so that I can trace it out???


Thanks Steve W.

'Bump' release generally indicates intermittent connections, but first check the TCC Switch on the brake pedal, also a prime source of failure.


May be combo TCC\Brake Lite on your truck. Brake wires may be orange (hot) and white, to combo switch on steering column, for brake lites.


Next, starting with the three (4L60E) or four (4L80E) connectors on the trans, unplug, inspect for oxidation\corrosion, and reseat the connections.


Do this throughout the trans harness, incl the sensor on the inj pump, working your way into the cab to the TCM, behind the glovebox


Most major libraries have one or more of the master auto-truck manuals, such as Chilton, Hollander, etc, with photo-print service.


Also, most autoparts houses carry Chilton and Haynes, with suitable diagrams of the pre-PCM trucks

Thanks --- it was the brake pedal switch.


Problem solved.


The Internet is great.