I am suprised you guys take everything on allpar as gospel, I have seen a ton of mistakes when reading different things on there. I have no idea however what it says about tranny fluid is true or not though.

I have heard the varnish theory but the only time I have seen varnish build up in any auto trans was in one that was totally toaseted, every band and clutch in it was fried. I have rebuilt a ton of rwd chrysler trans and that was the only one I ever saw with varnish. It was a core from a JY and have no idea of the history of it.

The only tranny fluid I have noticed any differance in the way it made a tranny shift is type F. I have a cheap and plentiful source of Honda atf z1 and have used it in a bunch of mopar trannys with every one of them still running fine. I have no idea what is in it but a honda dipstick says use dexron mercon or this.

Mopar has built a ton of puny trannys recently and the "softer shift" crap is what seems to be burning them up not the fluid. I worked at a dodge dealer quite a while and was shocked at the trans relibility problems, trannys going out before the first fluid change was even due. I remember the tranny guy replaceing a couple complete trannys right off the truck with virtually no miles on them he also replaced a ton of valve bodies under warranty, funny thing though, he replaced the entire trans for the same problems when it wasn't warranty.