I installed the 2,500# Pressure Relief Valve (PRV) in my F40 at the urging of my supplier. The Changes Section of the repair manual discusses a strengthened lift cover with the stronger PRV. Should I replace the 2,500# PRV with the 2,000# PRV? November 3, 2014.
I believe in the original recommendations in the MHF factory service manual. The 2500 lbs. relief valve is correct for the F-40. According to Service Bulletin 56-19, the F-40s were equipped with a heavier top cover and heavier lift links before the TO-35 was. I believe there is a part number for the top cover so you can check to see if you have the first version of the strengthened top cover. There have been several improvements to strengthen the top cover during production, including current production. It is possible a 2,000 lbs relief valve was installed in the past. If you choose to replace it with the same valve, Massey Ferguson does not supply the part. It is likely only available through aftermarket suppliers.