1998 GMC GMC TRUCK User Comment / Complaint

I purchased a used 1998 gmc extend-cab 4x4 pick-up here in tn.. i have had very good service from it until i made a trip 2 1/2 hrs. from my home. when i arrived at my destination i parked the truck, visited for awhile. when i was preparing to make the trip back i started my truck and as i put it in reverse i heard what sounded like to clanks coming from the rear, the person i was visiting also heard it from outside the vehicle. when this happened i couldn't get the truck to move, so we had to physically move it over to the side of the drive. after some time i was finally able to get it out onto the highway where i was able to get the truck to move only by giving it just a little gas and then letting up just enough so that the gears would change, this i had to do all the way home and then to get it to a garage. i was told that i would need a new transmission, well i figured that the truck was not old enough to need a transmission since it only had somewhere around 65,000 miles on it and had been very well taken care of by the previous owner and myself. the garage looked into recalls for that specific make and model of truck and was told that there had been recalls for it but not on mine because it was built in another place, now this sounds ridiculous to me, but don't know how or where to begin to find out anything about it. i have since had to put a new transmission in this vehicle because i needed my transportation. i am hoping you can advise on this situation or at least point me in the right direction. thank you, kay haynes.