I thought , and I know that I should not think, is the 3B1 had two choices of transmissions the 600 series or the 900 series. the 600 has the standard engine driven pump and the 900 has the transmission mounted pump. That is why the 900 series are so popular on Soloy conversions etc, so check and make sure that you know which model you are flying.
I have to check out my flight manual and I will come with the specs if you like.
I was 40 nm from home in a KH-4 and the pump spline sheared. apart from a sore arm it was not so bad.