why does my trans not always shift into reverse

Without having some symptoms to go on, it can be anything. Since your transmission is electronically controlled it could be something as minor as a shift actuator or sensor to something as major as needing a new transmission. Dodge has not been known for real reliable transmissions.

its a dodge the electrical sucks i got a 97 Dakota and had to rewire the whole thing. start small check the wires.

does it shift into 2nd if not th gar is gon or th gands arebad

the tranny lines line to leak a lot on that model. Check your fluid and the tranny hoses for any leaks. also check the shift silinode that is rigtgh next to the lines at the tranny. If that is leaking replace the gasket. it deosn take much to lose a gear in these trannies. Do you have all forward gears?

Yes all forward gears work

I put a new selnoid on it and lost what years I had before I changed it and that didn't fix it and I only have low gear