The stock axle sleeve on a Cub Cadet LT50 is a poor design and can cause the seal on the axle to start leaking. This is because the design of the stock sleeve has pointed edges instead of a continuous shape all the way around. I designed this one after I had to replace the axle seal so that there is nothing to rip seal anymore. The ID of the sleeve is the same as the factory one the only difference is that the end that makes contact with the body of the axle housing and seal is flared continuously all the way around instead of having several flared points. Additionally, a replacement sleeve costs around $6 each where printing one is much cheaper. I printed it in PLA and don't know how long this will hold up, but it seems to be doing ok.
My mower is an LT50 from 2015, but the model of the rear end is as follows:
Tuff Torq 7A646084590 or MTD 618-06972
Since these are the same part and MTD makes a bunch of different mowers, there are probably other mowers that this part will fit on as well.
The author hasn't provided the model origin yet.