Wrong Transmission Fluid

I understand that Dexron transmission fluid is not to be used in Chrysler
front-wheel drive transmissions, and that the correct fluid to use is
ATF+4.
I¹ve also heard that wear and damage can result from using the wrong
fluid.

My ¹98 Town & Country transmission was recently overhauled by a local
transmission shop.  About 200 miles later, the trans started having
trouble
shifting and was slipping badly.  Rather than take it back to the same
shop,
I took it to the local Chrysler dealer.  They took it apart and showed me
the disassembled transmission.  It appeared that the original shop did
rebuild it correctly, replacing the clutches and gears.  But the clutches
were badly burnt and had to be replaced again.  It was then that I found
out
that the original shop used a Dexron/Mercon fluid instead of ATF+4.

My question is:  Could using the wrong fluid have caused the clutches to
burn out so quickly?   I don¹t see any other explanation.  Wouldn¹t this
be
considered negligence or incompetence on the part of the people who used
the
wrong fluid?

Also: What is it about Dexron that causes damage to Chrysler
transmissions?

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