They were wrong, see my next post below!!Just got back from the dealer, and have resolved at least one question. Both the service writer and one of the mechanics told me that only the rear diff. requires 4oz of friction modifier. They said any brand would be OK. There are some sort of clutch plates in the rear end (viscous coupler?) that require the additive.
Also the transfer case (J 140) requires ATF+4, any other is something else(didn't ask)
BTW, this is for my 2006 3.7, hope this helps.
EDIT-Picked a bottle up today, about $8.