sometimes when buying/trading like that you can get the short end of the stick even on here and end up eating a shit sandwich.
Bought a truck off here a month or so ago, trans pan was leaking i figured no big deal, shifted smooth when i test drove down the street, but on the way home(3 hr drive and he wouldnt meet me half way eather) the TC started to shudder going up hills pretty bad, but at the time I couldnt figure out what was going on or why it was shaking. Called the guy a few days later and he says it never did it when he had it and "good luck". Got home and drained the pan a few weeks later after trying a few diffrent things and there was a ton of metal shavings in the trans filter.
That was my worst fear when buying this truck was that I was gunna have to put a trans in it right away after buying and it happened in less than 1000 miles. Sure Im still sour about having to drop another almost 2 grand into my new to me truck(already replaced wheel hubs and alternator) but really I cant be too mad cause I signed and bought the truck AS-IS and knew the risks involved and proceeded anyways and now I got the short end of the stick. Nothing to do other than eat my sandwich and smile. Never again I can tell you will i trust someones word.. If someone wants 5 grand or more from me Im gunna put some miles on it before hand to know what im buying or no sale.
When buying a dodge, front end parts and transmissions are usally the problem areas so that should have been the first thing you looked at or checked... not that im saying he didnt take you for a ride on this but you have to go though them with a fine tooth comb and make a decision and stick with it.