If the box will adjust to the tolerances in the manual it does not need to be rebuilt. If the steering is still sloppy after the box is adjusted to tolerance something else is worn out.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.