I bought 1990 W350 that now has a Dana 44 (inverted hubs) from a 78 M880 truck. Problem is the pinion bearing is toast and I was wondering if these Dana 44's use the same parts as a regular Dana 44 HD? Would I be better off fixing this one or just buying a different used regular Dana 44HD (8 lug)? I can't seem to find much on the net about these diffs......any and all help would be great! Thanks!

tlbsdart@aol.com

The full time Dana 44F is pretty much the same as the non-full time 44F version, as far as the center section goes. It should take the same bearings as a later model Dana 44F. Even the carrier and carrier bearings should be interchangeable.
As you probably already know, everything from the steering knuckles out is different..but could be swapped for non-full time parts, of someone wished to do so. Just be aware that some of the 80's models went to a Central Disconnect system for the 4x4 activation. Shouldn't effect the center carrier/pinion bearing stuff though.

If you keep the full time setup...GREASE THE FRONT HUB BEARINGS!!! You gotta pull the wheels off to do it, and they are VERY often overlooked.

Basically, pull the wheels
Look through the hole in the rotor/hub assembly, as you slowly spin the rotor. Eventually, you should see a grease zerk. Grease it often! Swapping hub bearings in these front ends, can be PITA, and pretty spendy too.