Got to admit I have not done that on a 446, but I did do it on a 646, which granted is quite different.

Near the end of my post on adding power steering I talk about how I added a filter: https://www.casecoltingersoll.com/threads/power-steering-added-to-646a.83875/

Generally you would put the filter in the return oil line, In a 646 this location is right before the oil cooler.

Make sure the filter you select can handle the volume - 8 - 10 Gpm. and any hoses you use are rated for HYDRAULIC Oil. That is NOT a "heater hose" in picture, its hydraulic return hose. AND., that is a BARBED fitting it attached to. There are too many stories of blowing hoses off steel lines on start up with cold engines and cold oil..

 

Got to admit I have not done that on a 446, but I did do it on a 646, which granted is quite different.

Near the end of my post on adding power steering I talk about how I added a filter: https://www.casecoltingersoll.com/threads/power-steering-added-to-646a.83875/

Generally you would put the filter in the return oil line, In a 646 this location is right before the oil cooler.

Make sure the filter you select can handle the volume - 8 - 10 Gpm. and any hoses you use are rated for HYDRAULIC Oil. That is NOT a "heater hose" in picture, its hydraulic return hose. AND., that is a BARBED fitting it attached to. There are too many stories of blowing hoses off steel lines on start up with cold engines and cold oil..

Back when I built my 646 I also added a filter in the same location. On mine I had a port on the base for a pressure gauge (that little boss on yours right above the word "instal....")

What I found was on a cold start the back pressure would momentarily flash to 500-750 psi and after a few minutes would drop down in the 100-200 range. Once warmed up it typically showed 25 to 50 PSI at full throttle.

On a couple of my tractors, I did play around with a ZINGA high pressure filter that attached to the hydraulic PTO. It was a bit bulky but effective.