transmission identification question

[robert]

I own a mis 70"s 450B, loader w/ backhoe attachment. Reverse only works part time and im hearing some pump noise, also have a small leak from the trans pump. I purshaced a factory service manual, part # TM1033, with plans to rebuild trans. The transmision in the book is a whole lot different than the one in my crawler. The model # that is riveted to the side of the trans is # TDC 33 430, powershift twindisc. my question is, are there different options of trans, and/or different service manuals. The shift gate on my crawler says there are 3 forward speeds-N-3reverse speeds. 3 high, forward or reverse has never worked since i have owned the machine, so im not sure if does have an actual 3 high speed. Can anyone enlighten me on some transsimision identification.