White 2-155 georotor shaft key breaking

White 2-155 georotor shaft key breaking

I have a late Series 2 with the updated georotor. The original bevel gears got damaged after the nut fell off the main pump drive shaft.
So I ordered a shaft and drive gear from Rock Valley Tractor Parts. We noticed the shaft used a 3/16x 3/4” woodruff #9 key instead of the 3/16x 1 1/8 #16 key the shaft we took out used. We installed them and it worked fine for a few days but then sheared. We replaced it again with a hardened key from agco and it sheared again. Turns out the shaft and gear we bought were from the earlier 2-155 tractors.
Now I have learned that the later georotor is 1.5” thick instead of 1” and the later shaft and gear have 24 to 26 teeth (ratio of 0.92) instead of the 26 to 24 teeth (ratio of 1.08) the older ones have. So it turns out that, it is now turning 17% faster while running a pump 50% bigger. That bigger load is likely the reason the smaller key shears.
Now I am looking for a solution.
Can a shop cut the key way to the longer/bigger size? And if so, would it handle the load after?
Would also using loctite (preferably blue) on the shaft help?
Failing that could I get the later 26 tooth shaft with the bigger key and match it up to the 26 tooth drive gear now on the gear pump drive shaft? If the tooth size and pitch are the same adjusting the spacing should work.
Has anyone tried doing any of this and does anyone know what will work or not?
I really don't want to take everything apart and change that drive gear all over again.
Note: The key way is tight and not worn so that's not the problem either.
The shaft seems to be hardened so I do not know how difficult it will be to cut that keyway bigger.

That is likely the issue and a bigger key can be cut.

Other item just to double check, you didn't mess with the unloader valve or the relief valve did you? Those cranked up will shear a key too.

We never touched those and did not have that trouble before changing those parts but it is possible. Is it easy to check them?

You didn't say if you changed out the gerotor or not , if not make sure it does not have flat spots worn into it , they can catch and cause it to shear. Also make sure that the inside and outside of the gerotor are put back "matched" .that can cause problems also. If your going to change out parts , look into a new style gerotor that is splined, obviously you will need a new shaft . These were found on the 6100 series whites.