Find an Exploder D35 unit or a D35 from a Ranger. An easy way to tell the differance is that the D28 on the BII's an early Rangers have 12 bolts holding the diff in place and the D35 have 10. The whole TTB has to be swapped, it's not just a matter of putting the D35 diff in place of the D28, they are way different. As far as I know the BII's never came with a true D35, just a fake hybrid. As far as being direct bolt in I don't know for sure, but they are real close. Check out www.rangerstation.com there use to be info on this swap there.
Later,
Jeff