580C what does this part do?

i've got a 580C, shuttle shift.

there is a hole right in the middle of the floor with a HEX shaped shaft in it.

according to the manuals I have that hole in the floor is where you check the trans fluid,

but my dip stick for that comes out over on the starter side of the engine.(even parts manual shows this...)

I couldnt find anywhere in the operators or service or parts manuals showing a HEX shaped shaft there.



thanks for any info on this