Im building my nv4500 and found a deal on a big input shaft because the bearing got lost, does it use a diffrent size bearing or the stock size. I know the retainer has a slightly larger opening for the larger shaft but dont know about the bearing

I Don't know for sure, but I would imagine it would be bigger as input shaft is bigger. How many bearings are there one or two, if two maybe one is same and one is bigger. Sorry I'm just mumbling. 

I would say call a transmission shop and see about getting the right bearing for the job. Personally, I never had an issue with 5th gear nut or the input shaft. I went all out and broke the mainshaft right at the 3rd / 4th syncro.

Ok thanks ill hve to try and find some info on it  the reason for wondering is the retainer is the same size to fit inr the trans case just didnt know if bearing size was diff or not