1983 grinding noise, Front diff?

[Slowdave777]

Hello everyone, My 83 makes a terrible grinding noise when the manual hubs are engaged. The truck also makes a similar noise with transfer case in 4wd and hubs unlocked and/or locked. I replaced the aisin manual hubs with a warn set to no avail. I did a complete knuckle kit from marlin as well as inner and outer bearings and races. New rotors and pads. new oil in front diff and t-case. I think Im down to front diff. or could it be the brass spindle bushings? Truck does have 255k on it. Any advice would be greatly appreciated.