You know, its amazing what you find sometimes, when you start looking.
Apparently "ATF+4" is a DC proprietary formula. Chrysler started mandating its use to maintain warranty coverage in most of its transmissions back in 2000. Until September of 2005, they refused to release its specifications or permit anyone else to make or sell it, meaning that the only place you could get it was from your friendly DC dealer. They also apparently instituted a program under which, in order for a dealer to buy ATF+4 in "bulk" containers for shop use, the dealer also had to buy specified amounts of other bulk oils from DC.
ILMA, a trade organization of independent lubruicant manufacturers, raised a stink with FTC, claiming that the refusal of DC to permit anyone else to make or sell ATF+4 was a violation of the Magnuson-Moss Warranty Act, because it effectively required you to have your transmission service done by a dealer to maintain warranty coverage. They also complained about the bulk oil program, claiming that tying the purchase of bulk ATF+4 (available only from DC) to purchases of other bulk oils (available from independent manufacturers/dealers) constituted an illegal restraint of trade.
Probably in response to the ILMA complaint, starting in September, 2005 DC began licensing others to make ATF+4. Anyone who makes ATF+4 under license must pay DC $1 per gallon for the priviledge.
After reading all this I have become of the opinion that Mobil 1 ATF will work fine in a Jeep transmission or transfer case. ExxonMobil recommends its use in Chrysler transmissions. They are probably just unwilling to pay DC $1 per gallon so they can call it ATF+4.
Go to
http://www.ilma.org and do a search for "ATF+4" if you want some interesting reading. The news release from 2005 about the licensing program is at
http://ilma.enewsletterpress.com/news/default.aspx?IID=63.