Ford A 64 tt2221-1 Allison tranny issues

Hi i have a Ford A 64 with an Allison TT22221-1 Trans in it. My problem is there is almost no power in the 2nd gear, Its like the clutch or torque converter is slipping or not working. In first gear, pushing into a snow pile it seems to have power, but when you put it in second and hit a hill the machine almost comes to a stop and the engine doesnt bog down at all. Can anybody tell me where the pressure test ports on the trans are so i can hook a gauge up to it, and if anybody has ever had problems like this and also where i could download a service manual?

Thanks so much for your time. Scott in Ottawa Canada