We are original owners of a 91GL automatic with 188 k.  The trans
started acting up 6 years ago and we had it rebuilt at a local shop
(Cottman).  That was my first mistake.  Anyway a few months after the
rebuild the van starts shifting funny and the overflow tank for the
antifreeze starts to well... overflow, but it isn't  orange color (or
green) but a pink color.  Yup... trans cooler leaked and tranny fluid
invaded the cooling system.  Had the cooler fixed by Cottman, then the
cooling system backflushed a few times. All seems well.  That was
around 138 k or so.  Of course I have since replaced the head gaskets
myself, flushed the system with a hose in my driveway, scrubbed out the
coolant reservoir tank, replaced a metal coolant pipe or two...  All in
all it was a hassle.  IF I had known then what the group is discussing
now I would have certainly had it replaced.  Maybe the logic should be
that if there is tranny work on an older transmisson then replace the
cooler?  or maybe it should just be don't go to Cottman Transmissions

Dan Erlandson