Our Family Vehicle before the Commander, was a 2002 Grand Caravan with the notorious 41TE/A604 Trans. Most people have that trans go out around 60k miles, if NOT often earlier.
I changed the fluid every 30k miles, and did the home flush (many do it, just run the cooler return to a bucket, idle the motor and pour in new fluid as the old pumps out).
My mini-van 41TE/A604 is still going strong at 181k miles.
Probably the biggest factor, I installed a Trans Temp Gauge and monitored and took action to keep trans temp down to reasonable levels. Without, there would been many times I overheated that trans.
I considered switching from ATF+4, to AMSOIL, several folks on Mini-Van boards said they had and got good results. Thing that swayed me away, Chrysler specially developed ATF+4 for the 41TE/A604, as well as ATF+, ATF+2 and ATF+3. They finally got it right by going Synthetic with ATF+4.
The Fact the AMSOIL Synthetic ATF is multi-vehicle and claims to meet/exceed specs for a variety of fluids including ATF+4, had me a little suspicious. I wasn't convinced it was really formulated to meet everything Chrysler specified for the 41TE/A604. I played it safe and stuck with ATF+4.
Now the Transfer Cases, that was DexronII for years, I'd think the AMSOIL Synthetic ATF would work great, if ATF+4 or DexronII was specified.
The W5A580? I'm NOT sure, is ATF+4 really necessary for the Trans? I know ATF+4 was specifically designed for the troublesome 41TE/A604. Chrysler started using ATF+4 for everything, part as a cost savings because they were buying it so much in bulk and part because it was superior to all the other ATF's they used and would work better with in any ATF application then what they you've used before.
My guess, the W5A580 would run fine with AMSOIL Synthetic ATF, but sure would like someone else to be the guinea pig for me. Also like to know if anyone had tried to do the DIY Flush, where you run the cooler return to a bucket and pour in new fluid as the old is pumped out.
But the Steering Rack? I suspect the Jeep Steering Rack is turning out like the 41TE/A604 trans, Chrysler came up with a better fluid to help address the problems. Since no one has put in writing their fluid meets/exceeds MS-10838, I thinks it probably best to stick to the Mopar Fluid.