Transmission ratio help.

I recently aquired a 1986 International S-1955. We are hoping to use it for hauling our 5th wheel. The truck has 24.5s and 11/24.5 tires on it, which were put on by a previous owner so they could use it as an over the road. It has a 5.29 rear end ratio. The truck has a mechanical injected DT-466. We wanted to find some specs on the transmission. It is a 6 speed. The model number is FS6106A. The serial #80284815. We wanted to find some specs and a list of the gear ratios. Any information would be greatly appreciated!

 

Thank you so much for the quick reply. We are trying to figure out what we want to do with the truck. Thanks again!