Originally Posted by subzali
Just to throw in my two cents - my shims were pretty far off when I went to measure. So someone had been in there before and messed it up. I at first put it back together the way it came apart but it leaked a few short months later. YMMV
I think that's the test. Once you get it together, drive in 4wd for a while, then see if it's leaking. I guess 40's don't have ABS sensors on them do they... do they still have those square plugs? You can stick something down there to see if it's soupy.. but then again, if it is then you're doing the whole thing over again. I guess I'd probably lean towards the SST, if you can afford to have the truck on stands until you find one.
What's the width of the groove on the axle- is it thicker than the Marlin seal? Wait, did you pull a Marlin seal out of it? Or just get those to put back in... hypothesis being if you just got the 40, and the PO did Marlin seals, then maybe he switched the shims by mistake and there you go that's why the soup. which means you likely need the SST to sort it out.