Good morning, I'm from Argentina
I do not know if the post is the right place I have a ram 1500 engine 5.7 hemi.
I have a problem which does not enter the reverse enters but the truck does not betray, I mean, it does not move backwards it is as if it would be in neutral
However, the direct one and passes all the changes forward, it has no problem, it does not mark any error.
Some solution was suddenly that this happened to be in the mud
I leave you my whassap in case you can help me more, thank you very much
+541160450131
This is my ram

 

Heyyou, looks a like a 4 gen.
What year is your truck?
Are you getting any trouble codes?
Have you checked the transmission fluid level? When was the last time the transmission fluid was changed?
Take a look at videos for Dodge Ram Transmission Re-Learn (or Quick Learn). You can disconnect your battery for 30 minutes then go through the quick learn steps to see what you get.

 

Definitely a 4th gen and at least a 2013 (vertical fog lights).