Eaton Fuller 10speed...

Get the model number off the data plate and head to Eaton's website. They have just about all the parts books and shop manuals available for free download.

 

Bad news is I'm about 98% sure you have to pull the auxillary section and partially disassemble it in order to replace the output shaft bearings.

 

Make sure output nut is tight.

 

If you tighten the nut and the yoke has anything over almost no play you probably have bigger problems.
We use a 1 inch impact and a 2 & 3/4 socket to tighten them. If that takes all or almost all of the play out you should be safe to install a new seal and possibly a wear ring. Nut is considered a one time use item.
When yokes run loose for long periods of time the bearing races can spin in the housings. They are harder than the housings and housing wears. That requires replacement of the rear housing to correct.
Lots of Eaton Fuller Road Ranger info on line.

 

Recommended torque used to be 450-500 ft/lbs, but newer crimped style nut is 650-700 ft/lbs. I believe off top of head it's a K4122.

 

Wow! I need a bigger wrench.

 

More than likely the yoke nut is loose mine did this awile back