Product review (5 stars): thanks for a great post. I also have the GE model GTWN4250D0WS ...
Echo the review posted by Dan'l 28 Sept 2016, thanks for a great post.  I also have the GE model GTWN4250D0WS and after 5 years of use all parts subjected to water were  corroded and covered in calcium deposits.  I had to soak the Hub Nut WH2X1193 in penetrating catalyst(B'laster PB-16) for 36 hours before it would break loose. Replaced it with a new one along with the split ring WH02X10265. The tub seal comes with the shaft assembly but you might want to replace the washer tub bearing WH2X1198 and the drive belt WH01X10302 while everything is disassembled.