Muncie PTO # TG6SU6004A3KX is a 54hp Air shift with a 7/8" 13SPLINE output for a direct pump bolt on.
This PTO will fit both the HT700 series in the HET, HEMTT, M915,M916s and the MT600 series in the 939s. They use a 60 series gear that will work on both transmission.
These are not pressure lubed PTOs as apparently the torque converter slings up plenty of fluid to coat the gears.
PTO costs around $882. Can be built in a day from muncie. In order to save money, order the PTO from a muncie distributor in another state than your own. Then have them drop ship it to you. This way you save on not paying the taxes on it and that can go towards shipping cost.
I did not like the clutch style shift of the Chelsea units.
You can not use this pump with a 53 series cross pump. The pump is too long and hits the transmission.