1984 gmc sierra plz hlp car drives bt juss crawls need answers

[1984gmcsierraguy]

hi any info is greatly appreciated i have a 1984 gmc sierra and when i put it in drive it did not go when i accelerated i had to put the pedal to the floor and then it just crawled forward same thing in reverse and the 4wd also the 4 wd does hold a park when in gear,it was in neutral when i was crawling forward was in neutral, i dont think its the tranny altogether theres no noise coming from it or smell of burning tranny fluid and the fluid was the right color and there was no metal shavings in the pan some plz help me narrow this down before i change the tranny and have the same problem, also when i put it in drive with it off it still rolls same with reverse, transfer case maybe tranny pump i dont know. also it is an automatic