1996 transmission question

I just got a 1996 taurus lx 3.0 dohc for free. It got hit and the whole care just got repainted with a custom house of color candy green. I just started driving the car since it got hit on the first day. The transmission shifts perfectly but I've read that these trannies are horrible. It has 144,000 on it. I wanted to change the fluid since it smelled kinda burned and was not too red anymore but my dad said not to because it would mess it up. I want to change the fluid, and filter. and then after that i want to get the whole system flushed to protect it from going out anytime soon. Has anybody had any experience with these trannies and flushes/ filter changes?

While I have never had any experience here, I always have heard that you must either keep it changed or never change the transmission fluid. It may be that if you haven't been changing it and you start changing it, you may loosen embedded metal particles in the transmission, causing it to jam/break. Dunno for sure, but that's just what I've heard.