My step van

hey guys my name is chros. i am in nned of assitiance. i have a chevy 1978 step van and it is acting werid. when i drove down the road going the posted speed, the transmission will slip out of gear. now the transmiossion has been flushedout many times, and the tranny pan and filter have been cleaned and replaced. what could be the matter?

What kind of things have the people that have been flushing your wallet,OH I mean your transmission been telling you?

It may need $1,200 or more or a used transmission. The broken or worn seal inside the transmission has to be changed, or the worn out clutches. You won’t achieve anything by flushing it or changing the filter.