I came home from work yesterday, and as I pulled into the driveway, my Explorer failed to go into gear. I gave it gas and the rpms went up but the vehicle moved nowhere. All fluids are fine, no lines are broken. The explorer will work in 4 wheel drive, crawling slowly, as it does in 1st and 2nd. It will not go into drive or reverse.The trans is automatic.

Please give me any possible ideas and or remedies to what is wrong. My father said it might be electrical. Money is an issue right now so i hope its something simple

Thanks