Re: 2001 Gran Marquis shifting problem
If it shifts on flat roads it might be the torque converter thats gone. I'd try a transmission fluid and filter change just to see if that helps at all if you haven't had one done recently. If anything else it's the cheapest way to diagnose. If the shop finds any metal particles in the fluid it'll be time for a rebuild.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!