Sorry, but I have no literature for a model 45.
Check old Motors manuals and the like, you'll find something eventually. I have picked up several large Spicer three ring binders full of service and parts manuals at flea markets, but unfortunately nothing as old as what you are looking for.

You may just have to guess at disassembly and reassembly, they are not very complicated.
Bearings and seals should be available from a regular bearing supply place just by giving them the numbers on the old ones.
I doubt you can adjust a worn input shaft bearing, but start taking it apart and see what you find.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-