I have done two transmission flushes to my Durango with no problems,
FF

 

The problem is that during transmission flushes they use a cheap mulch-vehical trans fluid that isn't supposed to be in your transmission in the first place. If you ask them to use ATF+4 fluid only the shops will look at you cross eyed and tell you that it is fine but they will charge you the fluid price difference, however they don't actually clean out the machine and change it. They simply know more than you, or they think they do.

Now if you go to the dealer you should get the right fluid, however any transmission flushing machines blow all the crap out of your filter into your transmission! See, that is the reason the filter is there in the first place, to filter the fluid. If you pressurize it most of the crap flushes all the way through your trans, the exact opposite of what you want.

To do it correctly on yours, you drop the pan, change the filters, replace the pan cover, fill it up, take the return line off the trans and place it into a bucket. Then start the truck and have someone tell you to turn it off after about 6 quarts goes into the bucket. Then reconnect the line and top off your trans fluid. This way you use the transmission to "Purge" the old fluid out the way it was built to run, not pressurize all the crap through it.

 

I used Royal Purple ATF in my Durango and Coronet. I changed all the fluids, engine, power steering and differentials to Royal Purple.