So really the o/d button does nothing. Clear now.. Brake drag could raise your rpm and waste gas, I think o/d would still work, however. TSS is easy to change if you don't have a rusted transmission casting (mine had to be drilled out NY salt!) A Florida car should be OK, but use b'laster penetrating oil on it anyways. That new sensor will smooth shifting a bit. I believe the o/d will still not work, a solenoid could be stuck "off" inside the transmission, definately get codes scanned. Let us know how it goes.