Tow, Jim, 2 down, MK and others,
Thanks for the heads up on the G-56. I am a bit skeptical with the "?" gearing on G-56 on the on-line chart. There would be virtually no reason to have ratios that close. But you never know what those guys at MB will come up with. With the dramatic increase in TQ in the Cummins, there seems to no longer be any need for a 'grannie gear' as you can just about let out the clutch in any gear and start moving.
That's why I would, after long consideration, go with the 3.42's and call it good. Larger pinion. If you start to lug, just downshift. We don't have to be in 6th gear all the time. Unless you were pulling a big trailer and have a heavy camper on board, then a higher numerical pig would be an asset.
jefe