Re: Over Drive not working.
Check out the shift solenoid. It's in the transmission so you'll have to drop the pan (similar case on the majority of vehicles).
If there are engine codes, be sure to get them read first with a scanner. If you're unsure, drive to an AutoZone and they'll check the vehicle at no charge.
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!