I suppose I should clarify my post about the GMC 450. This truck had the double-reduction Timken axle not the planetary type. Having never worked on the planetary type I can't say for sure but I suppose that the worn dog-clutch issue would be similar.

1951 3800 1-ton
"Earning its keep from the get-go"
In the DITY Gallery
1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.