Shifting Issue or Interchange Trans

Hi all, I am new here so you may have answered this before but here goes .....
I have a 92 Caravan with trans issues. At first the trans would have problems being stuck in 2nd gear , shut off and restart a couple of times and it would shift fine, so i researched it and found the shift soleniod was bad, rattled when taken off and inspected. I replaced soleniod pack and it was shifting ok only issue next day was when driving down the road the trans would go into neutral. 2 weeks later still doing neutral while driving down road but not often. I drove 650 miles on a vacation trip and it went into neutral twice and on the return trip home a BUNCH of times. So while moving down the road I would put van in nuetral and shut off and restart while moving, place van back in drive and it would be fine. So I either need help with if its a switch or will my 1990 caravan trans ( that is fresh rebuild 3 months ago ) interchange with my 92?

It would be best to see what's causing the problem with the current transmission. You will need to buy a scanner that will work. Some shops will scan for a small charge. It could be as simple as a ground wire problem.

hmmmm when going over train tracks today the dang thing did the second gear only again ..... do you have any previous experience with the wiring issue as to a common area the ground fault is at ??? like 90-92 tempos had a problem with wiring shorting out altenators. I bought a BUNCH of these cars then cheap cuz if you lifted the radiators you would find a pinched wire. got any ideas where to start looking????

Well, you can try this:
http://www.robskorner.org/faqs/Trans/a604intlimpin.html

I just wish it said what size drill bit to use. It sure sounds electrical, unless the fluid is low.

thanks