Hopefully you can find some serial numbers....Blade s/n should be on the RH rear near the top of the mold board. Most likely a #17C5001-up for the angle dozer or 17C1 to 17C5000 or 84C1-up for the straight blade.
Uses the #46 Hydraulic control, look for a s/n plate on the left hand side of the rear face of the Hydraulic Control tank assembly. Most likely a
2Wxxxx number. This will get you the parts breakdown.
As far as service and repair you will need the Servicemens Reference Book Form #12914 Hydraulic Controls and Equipment.
First place to go looking would be ebay.
PS, I show 3T production ending in 1955.