Tractor Repair: IH 1086, sprag clutch, clutch

Question
My 1977 IH 1086 cluch peddle fills to be weak or at the top it pulls a 18 foot dick and plow with no trouble with no slipage but when i use the TA going from high to low it fills like the cluch is sliping but not all the time infact it is rare and  ptos work good ido get the trans light every time i depress the cluch peddle and gos out when i release the peddle and never comes on under a load

Answer
Hello,

  If it only slips when shifting the TA from high to low, then the mechanical sprag clutch inside the TA is worn out and will need to be replaced.  If the main clutch slipped, it wouldn't matter if the TA was in high or low, you would feel it slip all the time.