My son bought a 96 ford f150 years ago and drove it a couple years until it quit running I hired 3 different mechanics and none of them seemed to be able to tell me why a couple said it was the computer,I ended up finding out it was the distributor,replaced it and got it running again the problem now is the transmission when it was parked the tranny was fine now it slips and clangs .I found a puddle of transmission fluid under the truck so I replaced the pan gasket and filter and put fluid back in any ideas as why it is doing this?