seriouse automatic transmission help! thanks for good answers!!

[Rebel831]

ok this is my little big problem. i got a 1990 nissan 240sx coupe for 300 dollars very good price considering no dents straight body, etc. well i went to pick this car up by towing it home. the last and original owner told me it the transmission went out in 2005 and since then he hasn't moved it, the next day in the morning i put in a new battery, fresh tank of gas, and in three years that it hadn't started vroom it came on in the first try. the guy told me that the transmission was completely bad and i shouldn't move it. (19 year olds dont listen) i took it for a test spin gosh it drove good until i got to a stop when it made this sound like metal rubbing against sand in a spinning motion. after that the car only goes is park, reverse, and third gear at all times while im driving. i can put the shifter to first but when i put it to second it jumps to third and stays there, ive tried going up to 118 in third and seeing if it will go into fourth but no luck. this is important, i dropped the transm. pan and the oil was as black as the motor oil (sh*t) and when i took out the filter i jiggled it around and like 8 ounces of metal shavings and other weird dodats came out. put new motor oil, tran oil. i got gear oil but i couldn't remove the plug tight like a sucker. but yea ive seen all the forums with similar problems but never a real answer that will really help. ohh and the motor is good, sorry for writing the bible but i wanted to have see it in my prospective. ill post pics of my car in the new peeps cuz i had gotten my car towed for driving sideways, hope i can get some help thanks to anybody listening.