727 no 3rd gear

A rebuild would replace all the lipseals, and seal-rings. Problem solved. And the rebuilder would spot a missing or swapped ball in a heartbeat; that's what they do, and they look for stuff like that.

But, one thing you can do, is have someone check the gov. pressure prior to pulling it down.This is very easy to do. It could be a cheap easy fix. Governors have been known to fall apart.
While lip-seals usually do not blow out catastrophically,and cast seal-rings I have seen go 200,000 miles and more;but, Kims experiences show that failures do happen.