what is this?

[Zep71]

I bought new gear boxes for my XL build. in the screw bag it has 2 little things i can't find in the manual
does anyone know what they are here is a pic

 

[olds97_lss]

Is it hollow?

 

[Zep71]

Is it hollow?

no its solid mad of metal i put them in the top hole in this pic

 

[olds97_lss]

Ah, yep. Forgot about those pins.