Mitsubishi Repair: 1992 Diamante problems, mitsubishi diamante, rebuilding a transmission

Question
I own a 92 mitsubishi diamante now coz I purchased this last year and I sent it back to the owner coz after 3 days of owning the car I noticed that the transmission is slipping. It doesnt go to third gear and it stays on 2nd gear then after that it's like going to neutral. And the RPM just go to 5000 to 6000 if you don't release your foot on the gas pedal.And another thing is that whenever I start from a stop it doesnt really pull that much it's like its struggling for power. And when I put it on reverse I can hear a big noise and the car just shakes like it was kicked from outside. Some told me that I need a transmission rebuilt or purchase a remanufactured transmission. But I'm not ready to spend that much coz I know that rebuilding a transmission is quite expensive, I wanna make sure first that it was really the transmission thats giving me this problem. and by the way there is no leak or anything from under my car. Some say that it might be cables or faulty computers thats causing it. Pls help thanx so much. God bless

Answer
Ron: First off what does the fluid look like? It is pink in color or is there two colors, brown/pink. Or is the fluid all brown and smells burnt? I would first change the fluid and filter but also buy at any parts store some conditioner for the transmission. See if that helps at all, with the transmission slipping that might help you. Yes the computer does run the transmission, if the computer is locking the transmission in 2 gear it is because it is picking up a problem in the system and so will not let the transmission shift. As to save it, still try the changing the fluid, filter and adding that conditioner. If that does not fix your problem then take the car to a transmission shop and they will be able to tell you if the transmission can get saved. Hope this helps and God bless: Linda