i have a 1972 duster the back up light comes on in rev off in neutral and comes back on in all forward gears its an auto tranny i changed the neutral safety/back up switch it is doin the same thing any help would be great

 

First thing I'd do is determine if it's a wiring problem. What happens when you disconnect the switch (key in run?) Does it do this all the time or just intermittently?

If it's not a wiring problem, it just about has to be damage inside the transmission, or something out of adjustment. I believe it's called the "comb"

You can download a 72 shop manual for free here:

(along with a few others)

Torqueflite starts on page 21-47 Checkout and adjustment of the neutral/ reverse switch is on page 21-79

http://www.forabodiesonly.com/mopar/...al%2C+download