Hi, this is my first time posting to a car forum, sorry if I sound ignorant about cars or anything.

I recently started having issues with my ford explorer, it is a 4.0L V6 4WD 1996 Ford Explorer. It started when I took my car home for the holidays, the transmission was slipping a little bit (but not anything I was immediately concerned about), I came home and the issue persisted. Over the course of around 2 months the transmission started slipping more and more until one day I put it into reverse, reversed it out of the drive way and then tried to put it into drive. It initially didn't do anything for about 2 minutes then it started moving forward and responding to the accelerator pedal, but it seemed as if something was stuck or pulling the car back. This persisted for about a week and I definitely should have taken it to a mechanic but it's my first time having a car and I assumed it was just cold weather and I had to let my car warm up. Each time I would go to drive the car the same issues were there but each time it engaged into reverse rather quickly but would take longer and longer each time I started my car to engage into drive, it sometimes would take more than 15 mins, but reverse always engaged rather quickly. Each time I would start my car I would drive it around the neighborhood to "warm the engine up" after waiting the time for it to engage, the warmer it got the better the gears shifted while driving. If I had just started it and didn't drive it around the neighborhood to "warm up" it would shift extremely poorly and would be unresponsive past 2k RPM(I believe thats when the gear shifts), but as the engine warmed up it would become more responsive. Unfortunately the last time I was able to drive the car I was taking it for the drive around the neighborhood to warm up, the car was feeling like it did the first time the issue came up and felt like something was pulling it back or something was stuck. I would stop the car and turn off then turn on the engine to see if that fixed anything, it didn't. I was driving it back to the house and the O/D light started flashing so I decided to just park it at the house and call a mechanic. When I was parking my car at home I tried to reverse into the spot and soon found that my car would not reverse at all, no matter how long I waited. I was able to get my car parked but ever since then it has not engaged into any gear, not even neutral. When I put my car into any gear now(neutral, reverse, 2nd/1st, drive, park) and try to rev the engine it jumps forward slightly as if the engine wants to pop out, but only when I put it into drive and rev the engine the car shakes a little bit. My car got way too close to the garage when I was testing and so I tried to put it into neutral and have my friends help me push it back a little, we had 4 decently built guys push it and it didn't even budge a little bit, I tried multiple times in different gears(reverse, neutral) and still nothing. So that leads me to believe I may have a stuck solenoid, but I'm unsure. I checked my transmission fluid multiple times when the engine was hot and the level was correct but the color was brown with a little bit of orange. During this ordeal I've called about 3-4 different mechanics and one of them told me to put DOT-3 brake fluid into the transmission fluid, but he also said that my transmission fluid should be brown rather than red because of the type, but on my dipstick it says to use mercon which I believe is red. Each mechanic has told me I would need a whole new transmission, but I don't want to jump the gun and spend a bunch of money that I don't have without going through all the steps to figure out if I need it replaced. I'm leaning towards a bad solenoid at the moment and that's just because the car wont engage into neutral and actually moves a little bit when I rev the engine in park/neutral. Can anyone confirm/deny what I'm saying or lead me to another possible problem rather than the solenoid? Thanks!!!