I just put my nv3500 back together but the input shaft wont turn. The output shaft turns just fine in neutral but when its put in gear it wont turn. The input shaft slides back and forth easily. Its something with the countershaft I imagine. I was having problems witj it binding up during reasembly on the area of 1st & 2nd sychronizer that is made made to the gear when it was machined. Has anybody ever had this problem before? Could my countershaft bearing in the rear half of the casing be upsidedown? I dont know what it could be other than the something with the countershaft cause metal "c" ring torqued down and seated the rear main on down in the housing. Any help is appreciated.