Does the '83 Eldorado have a 4 speed automatic with lock up converter or is it really a 3 speed with the torque converter lock up providing a '4th' gear? I don't ever feel the torque converter locking or unlocking.

Thanks in advance for your comments!

 

Reasons for the no lockup could be several.Check for 12 v at the solenoid or maybe bad connectors.Defective pressure switch or converter clutch apply valve stuck. Have you kept the tranny oil clean on a prescribed basis??

 

That car has the 325-4L trans, which IS an Overdrive/4 speed unit, with TCC(torque converter lock-up)
No lock-up could be a brake switch that is not adjusted properly. Does the cruise control work? If so, when you press on the brake, does it dis-engage? It is the same brake switch for the cruize and the TCC.