Sheldon 12” Lathe TU 1248 P Change Gear Ratios

Hello. Chris Hamilton here. New to the forum.
I have a Sheldon 12” Lathe TU 1248 P and I am missing a single change gear which connects the spindle to the auto feed. Attached pictures below.
My questions for you guys are how to accurately decide which toothed gear I need for the Lathe to cut Standard American Threads. What would the stock gears be? It seems as though with what gears I currently have this may be set of gears to cut metric threads. Any helpers here?
Hopefully I have provided the info someone needs to accurately point me in the right direction. Thanks in advance for any info you guys can provide.
My thoughts are to provide a gear manufacturer the proper info in order for them to supply the gear or gears I need to cut American threads on this machine.

Not seeing your pics. When you say 'connects the spindle to the. . .' are you referring to the fwd/rev toggle gears? All of the gears in the train connect the spindle to the auto drive, but the toggles are first in contact with the gear on the back of the spindle. They are neither metric nor imperial and the only relevance tooth count has is whether or not they'll fit the space and move in and out with the proper clearance.