I swapped the 3.54s out of my 60 for a nice used set of 4.10s. Had to add 1 shim to get the pinion bearing preload "perfect". I dropped the carrier in and it has around .004-.006 backlash all the way around. Nice tooth contact pattern. Is it too tight? I'd rather be on the tight side than the loose side and I know there's room for a film of oil between the teeth. Anyone have the specs? Also any opinion about running synthetic 75-140 in a Dana 60, with the additive of course. THANKS!

Used gears usually set up between .008"-.010" backlash. Any tighter causes the edge of the teeth to ride in the rough and howl.

I like conventional 85 W 140 gear lube. Synthetics make clutch type sure-grips a little lazy.

At 004-006, a couple of blasts and you 'll be right there at 008-010.