Welcome to the board and to the cub family!
If you go to the Cub Manual link below, there is more than enough info to help you with your questions.
Engine oil - 30w, Gear Oil - 90 W, Hydraulic Fluid - Hy Trans
Also, at the top of this forum is a sticky note - Announcement: New Members and Visitors, Please READ. You will find all the links you need to get the info required. As for the element - the cross ref numbers for Napa etc are on the CUB FAQ's link there. The manual server has the owners manual, the service manuals and tons of other stuff. Lots to read.
Don't forget to order the TC-37F Parts Manual and the GSS-1411 Service Manual to accompany your Owner's Manual. They are all available at http://www.binderbooks.com
Those three manuals are intrinsic to the good health of your Cub.