John Deere service centers have a red dye made to be added to oil so you can see it on the stick. I put it in my Mahindra fluid. Now I can see it and don't have to guess.
My 5500 trany and hydro are on the rear. The square plug on top of the rear end housing has a dipstick attached for hydro and down below rig right the PTO on right side is a plug for the tranny