No need to pull the radiator. Front pump MUST come out. In my situation - I had a brand new pump ready to go in anyway. I was just looking for an excuse. The original Cessna pump was completely worn out. I put a new Webster-Danfoss in (direct Cessna replacement).
My drive was still working but the backhoe would barely work once hot. Strangely - the front loader still seemed to work. I finally pulled out the front pump and it was completely worn out. NO way to fix. I also found the pump drive was just ready to stop turning. It was all hanging by a thread and all splines were hammered something awful. Note that this machine had been run for years with the hydraulic filter missing. That seems to be common with 3414s.
I had to pull off the front weights, grille, and then the front pump. Easy job. The hardest part of the whole deal was making an adapter plate to make a Ford pump-drive plate to the IH crank-pulley. I made a round plate from 5/16" steel and drilled holes to match the crank pulley and the new Ford hub. It's nice now that all the parts are standard and available here cheap.
When all done with the new drive, pump, hydraulic oil and new NAPA filter in the tank - it digs like a new machine. I'm amazed at the difference. I also put in a new PS/swing pump that I got from a place in England.