you probably have some variant of this H350 Timken axle.

https://photos.google.com/photo/AF1QipP3SonHOgvLbAV5CPxUJMg_NtucB4oRJPhXhDYO

They were put behind Hydramatics. They had a real wide split. You ran the Hydramatic through the gears in low range and then started all over in high range. It was common to lock them in high range when a Hydra went bad and was replaced with a standard.