Fitting size and thread in radiator drain of D8 13A

The dozer is three hours away in a remote area not close to a hardware store.  Can anyone tell me what size the threads are in the radiator drain.  I put in new antifreeze and after flushing the system, I have a small gasket that wants to seep.  I was hope to drain it down but with the belly pan there is no way to not contaminate it unless I can screw a fitting into the drain fitting and attach a hose.  Thanks. 

I think it is 1/2NPT thread. Possibly 1/4NPT. grab one of each and bring along. They are only a couple bucks each.

all threads on these older machines are SAE so npt, nps unf unc uns maybe unef all pipe fitting should be npt or nps.