Lol, that's funny, I noticed that also
Yep, as has been stated, 35s is generally regarded as the upper limit for the D35. There are several here that do run tires as big as 38s without much breakage though (Warrlord (aka Thumper) is another who ran 38" TSLs & a Detroit on his big huge Supercab for a few years rockcrawling, with (IIRC) only two broken shafts during that time (not running the 760s either). I think he has 37" IROKs on it now IIRC.
You'll also find the general tiresize limits for a D44 front are not much greater than for the D35 (36-37" or so). You should be fine.
That sounds like a great idea at first, problem is... the stock hubs are SSOOOOOOO weak (probably not even 50% as strong as the shafts), they just turn into a major PITA annoyance (both for you and others around you). They just break too damn easy
Cheapthrill, you know for sure that's a jeep hub? (is that yours?) What's the story on it? (and I'd still sure as hell be impressed with however much it took to bust that compared to a stock hub)
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Edit:
Here a link to the D44 outer swap
http://www.therangerstation.com/Magazine/winter2007/44knuckleswap.htm
I run the stock D35 outers on mine and have never had a problem with them.