If you had a way to simulate pressure through and air line or something you could compare resistances. It would be my guess they're pretty similar though.
My stock started dropping pressure at top end evidenced by an inline gauge, replaced with walbro and all is good. I have the 6L though so may be different for say the 5.3.
Just eating through a big mud hole in low range. Either the input shaft or pump went out. I think it's the pump. Would just need to pull a cooler line to find out. It's a built tranny as of last summer.