jd 420c engine/water pump/rearend questions

[mc_mike]

I recently acquired another JD 420 5 roller machine with the 90 loader. I just removed the grill guard and the radiator to get at the water pump because it would not turn. The pump is busted, probably from water in the system at one time that froze. I don't want to tear the whole motor down to check for cracks is there some other way? Should I make a couple plates to put over the water outlets/inlets and put an air fitting and pressurize? Where are the weak points of the engine's water jacket? I have checked the oil and there is no water in there and it is not milky. Any ideas? Also the machine has a busted rear end ring gear, I have another transmission I could just swap in or would it be easier to change the ring and pinion? Either way I think I need to spilt the crawler? Any help would be appreciated, thanks.

[Howard Yoder]

If you have another 420 that you can live without for a while i would rob the pump off of it you would only be out a couble of gaskets. The problem is I had a 720 with a busted block that leaked pretty good and it would take about 6 to 8 hours of operation before the oil would turn gray or milky. It would surprise me that nothing else would be broke but then you never know. Good luck