Originally Posted by
Prince Valiant
Depends on maintenance really...it's particular to the fluid you use. Many companies use unique fluids (honda, nissan, ford, toyota...) as does the 46re (requires minimum ATF+3 or +4). Many shops, even some dealers, will simply uses a less expensive universal fluid such as dexron, and simply use a bottle of additives to bring it up to the specs of ATF+4...this usually doesn't work though.
Basically what happens is this...use a fluid that's not recommended, and the transmission clutches and bands slips a little, for which the computer tries to compensate for...this leads to increased wear, more slippage, and greater tightening. In the old "ultra-drive" days (chryslers first computer controlled transmission), failure could occur within 30 miles of the fluid change....
Changing it back can help...when the wrong fluid was used in the old days, the computer had to be reflashed...not sure that this is the case now.
They used to blame the failures on a number of things...primarily not enough fluid circulation in O/D, particularly to the O/D unit itself (there were "fixes", but this wasn't the case), and a check-ball within the trans cooler line that tended to gunk up...turns out, they were misreading the cause of the failures...it was the fluid.
Basically, if you look up an R/T and it's got a good working trans then it should be fine...when you have it serviced, make sure actual ATF+4 is used when flushing the trans.