So I got my high school dream car..I paid 3K..its a 5.7 and an origional Florida car, nice underside since no snow/salt rust. The owner advised me the trans would need a rebuild and it drove fine all last week after I bought it. Bout today I backed out of my garage and BAM..a puddle of tranny fluid. Put more fluid and it drives..Heard the distinct knock under the floorboardwhen accelerating and its slips from 1-2 and 2-3. Question, can this be a dry rot plug (leak), and dry rot vacuum cable..and as far as the knock maybey a bad mount?

 

You could have a dry rotten seal somewhere as well as a vacum hose but the slip is in the clutch packs I would take it to a trans shop and let them tell you if it needs to be rebuilt if the guy told you it needed one then likely it needs to be rebuilt The knocking noise could be the trans mount or it could be the meshing of the wore out clutches inside the trans but to be honest with you I dont know what it could be without actually driving the car myself and seeing exactly what you feel hear and see you know I hope I helped you out with my vauge awnser but I dont know what else to say here