This is a simple video explaining what the P R N D 2 1 settings mean, and why or why not to use them, including the most frequent question I see posted online – whether or not to O/D on or O/D off (overdrive on or off). The owner’s manual and supplement that comes with these cars lists the very limited reasons to turn off O/D.
0:00 Ford Crown Victoria police interceptor P71 P7B automatic transmission 4R-70 4R-75
0:35 P is park (self explanatory)
0:40 R is reverse (self explanatory)
0:43 N is neutral – can start car in P or N – can push car in N
0:59 1 – first gear – transmission remains in 1st gear
1:26 2 – second gear – transmission remains in 2nd gear (does not shift 1-2 like other cars)
2:04 D – drive – transmission shifts between all gears 1, 2, 3, and 4 which is overdrive
2:46 O/D off – turns off overdrive – transmission shifts between 1, 2, and 3 only
4:00 normal driving – keep overdrive on for theoretical best fuel economy