There are several reasons why exotic lubricants do not get more public attention or acceptance. One of the strongest ones is that the public usually regards cars and trucks as throw-away items; and thus sees little or no value in extending or prolonging their life. So there would be little profit potential in advertising such producuts. On the other hand; high performance motorcycles often produce enough stress on lubricants that the conventional stuff just doesn't hold up. And in those cases; synthetic lubricants are advertised for that market and are selling well. Simlarly, racers typically use synthetics.
Synthetic tranny fluids will produce little noticeable change in fuel economy in a truck; and Chrysler is very strict about automatic tranny lubricants meeting their specific standards; so not all synthetic tranny fluid will be approved for this application. But if you can find one that is Chrysler approved for this model, I would go for it mainly because of the extended life.
Synthetic engine oil probably carries a greater potential for fuel economy improvement than does synthetic tranny lubricant; mainly because the benefits are not only in friction reduction; but also in improving the sealing of the piston rings, and that has significant effects on performance. But here, we must distinguish between gasoline and diesel engines; and also distinguish between manual and automatic transmissions. The lubricant viscisities and formulations which work best in a gas engine will not be the same as the ones which work best in a diesel. Transmission lubricants also are similarly specialized.
If you are interested in this sort of stuff; do not overlook the lubrication of the differential. There now are some excellent synthetic gear oils; which greatly outperform their petroleum equivalents. Synthetic gear oils are relatively new and uncommon; and have had the greatest testing and development in heavy duty trucks and in racing motorcycles; so I use those sources for these particular products. They sure do a lot to quiet down differentials and trasaxles.
And there are important technical differences between grades of gear oil; which must be considered before selecting one. Gear oil designed primarily for manual transmissions will not contain the needed additives for use in transaxles (combined transmission and differential units; such as are commonly found in front wheel drive cars) or differentials. Transaxles and differentials have hypoid gears in them; which need specific lubricants. Gear oil is classified by GL ratings. GL1 to GL3 has few additives. GL5 has hypoid specific additives required for manual transaxles.
For more information on synthetic lubricants; check out http://www.spectro-oils.com/
The transaxle in my 1990 Geo Metro has always been very sensitive to the lubricant used. The manufacturer called for GL5 SAE 80. I used Red Line GL5 75W-90 in it for years; but I had the front CV axles replaced some time ago, and did not know that the shop drained the transaxle and put some generic crap in it. Shortly thereafter; the transmission began howling in third gear; and I began contemplating having to replace the transmission. Then it dawned on me that the shop that changed the axles probably drained the synthetic gear oil. Red Line is a good lubricant; but I did not feel it was good enough to bring a transaxle back from the grave. I knew from experience that Spectro makes the best gear oils that are available; and then found out that they came out with a new gear oil which is specifically designed to quiet down the new Harley Davidson 6 speed transmission (which is notoriously noisy). So I decided to go for the best, and bought 3 quarts of this product; which is called Spectro Heavy Duty Platinum 6 speed transmission oil GL5 75W-140 http://www.spectro-oils.com/?p=273 This product costs about $22 per quart!!!!! but it turned out to save my transaxle; so I considered it a great bargain.