PLEASE HELP FISHER PLOW WON'T GO DOWN?

HELP I HAVE A FISHER PLOW ITS NOT THE MINUTE MOUNT AND I WAS PLOWING TODAY AND I PUT THE PLOW UP THEN WHEN I GO TO PUT IT DOWN IT GOES DOWN REALLY SLOW. THEN I RAISED THE PLOW AGAIN AND IT DID NOT GO DOWN?? WHAT COULD THIS BE???PLEASE HELP THANKYOU