91C1500sleeper

I have a 91 1500 with a mildly built 350. I rebuilt a 700r4 when I installed the fresh motor and burnt the trans real quick. So I spent or should I say wasted the money on a monster stage 2 400 trans. Been running it for the past 2 years and it's starting to act up. The fluid is normal color and smells normal. Can't find anything loose or out of adjustment.

I can't get them to stand behind their warranty cause I'm passed the mileage and time frame. Wouldn't waste my time anyway their customer service sucks!

So do I find the 5 speed and parts to convert to a manny or opt for another 4 speed auto. If I was to keep it auto I want to know what 4l??? trans is not controlled via a tv cable that if not installed and adjusted correctly won't burn it up. The newer versions are computer controlled right? There is no factory computer in my truck anymore. Since installing the Fitech I removed the stocker.

Any input or ideas would be greatly appreciated.