ok when i drive my car after a few seconds it goes into neutral and won’t drive and hard to
back up
Apparently you have this message board confused with www.psychicmechanics.com, where they would already know what kind of car you have, whether it is automatic or standard, how many miles the car has, what the service history is, whether the fluid is at the right level, and what color the fluid is.
Right on, how does the logic escape them ? Basic info at the outset, we should’t need to baby sit. many target diagnostics can’t be anticipated but c’mon people , basic info basic info basic info.
Make, model, mileage, etc. really won’t make much difference in this case.
If the transmission is an automatic check the fluid. If the level is normal then the transmission is shot and will need overhauled. If the fluid is low put fluid in it and try again. Be advised you may have ruined the transmission anyway by operating it with less than enough fluid in it.
If the transmission is a manual the clutch is shot.
Worst post of the day award.
You could have some obvious broken stuff underneath and some lucky mechanic could spot it right away. The worst thing that could happen is that you could type like heck and get my advice on trannys.
Yeah, guys and making a bunch of “me too” posts that bump the thread back up to the top proved really useful as well.
Anyway, I have to say, what you described doesn’t sound good. First start by just checking the fluid level in the transmission, and looking at the quality of the fluid on the dipstick. If it is obviously burnt or has particulate in it, I’d try a simple flush and see if that does anything for you. Unfortunately, if reverse isn’t working well and it’s not staying in gear, and it IS full of fluid, you’re probably going to need to take it to a transmission professional (the obligatory “stay away from chains like AAMCO” goes here) and I doubt they’ll have good news for you. 
I would say that it is not ok. Okay?