1995 Dodge Neon transmission fluid leaks out?

I have a 1995 dodge neon 4 cylinder automatic trans. With about 150,000 miles on it.I bought the car after it sit for about 2 years with complaint of trans. Fluid leaks out.I found a bent and leaking trans. Pan so I replaced pan gasket and filter. Car shifts fine from 1st to 2nd but will not shift to 3rd until it is warmed up good and I have to put shifter I neutral and raise rpms and put back in drive and it will shift to 3rd. Trans. Shifts from 3rd back to 1st at stop. When trans. Is cold it will not shift to reverse unless you rev engine and then after a little while it slams into reverse. Fluid is fine and no burned smell, what could be the ploblem and is there something I can do to repair myself?