Is it worth to you to replace the sump? Model /type or spec numbers could be helpful. If a used engine is your best option- maybe you will come across someone who has a trcator w/ a bad trans- and just wants it out of there!

Would it be possible to use a piece of 1/8" steel plate under the bottom. Drill a hole as needed, and then use the JB weld between the piece of plate and the engine. If you have a grinder you might make a cut like an upside down V in the cracked area in a couple of places for more JB. Make sure that all the metal is very, very clean before using the JB. Mabey use carb cleaner. Also, when you put the bolt in have a semi large washer under the head.

If...............this were simply a matter of a "cosmetic leak" of oil LB Weld or other such epoxy would be OK, if given the proper prep and application method.
It WILL NOT WORK for this type of damage because the area of the sump that has sustained damage is a STRUCTURAL casting.
The sump and the 4 mounting bolt "feet" actively transmit the engine reactive torque forces into the frame of the tractor, and neither JB Weld nor any other type of epoxy/adhesive/glue/or chewing gum will bear the load.
Your choices are:
Welding shop to TIG weld the crack
New sump
Used sump
New Engine
Used engine

Once again we can not read minds. WHAT engine do you have? I MAY have a used sump. Only fix with any chance of success is welding which will cost at least 4 times what a good used sump will.

Walt Conner
wconner5 at frontier dot com