Torque converter --- Truck will not coast freely in OD

My 98 chev. 1500 pickup will not coast freely if I have beeen over 45 MPH. If I touch the brake, it will release the lockup or it will release by itself somewhere around 30. All else works good. LS and your question is? The question is, Why does the converter stay locked up. It feels like when I let off of the gas, the engine is slowing the truck down as if I had shifted down. When I touch the brake, the tach drops off and then the truck coasts freely. Took a chance and replaced the TPS. No change but maybe this will help in troubleshooting. Any help will be appreciated. Thx. LS Seems that PCM doesn't know that you are slowing down for some reason and it isn't disengaging the torque converter solenoid. Check engine light on? If you had access to a scanner with data reading capabilities you could monitor the vehicle speed sensor, TPS, the command from the PCM to engage or disengage the TCC solenoid. You could ask Transman on this site if he has any ideas. I am surely thinking that it is electrical and not inside the trans. I try and get some more info in the next couple of days.Car Repair Talk's forum.