Quote:

... I pulled the axle out and shined a flashlight down the tube and saw what appeared to be a thrust button. I tried fishing it out, but it just dropped down inside the differential housing.



Just a bit of useful "100 miles from nowhere" info:

Early thrust buttons used a roll pin between the buttons, this was the design that was prone to having the button(s) fall in when an axle was removed. Later versions used what is almost a "nail", you peened over the headless end when installing.

The point is that both systems were just an assembly aid. You can stick the buttons in with heavy grease, daub of RTV, whatever, pop the pig and axles in, you'll be fine...until next time you pull the axles, of course.

Natch, be sure the pin isn't floating in there somewhere.

Rick