When I inspected this vehicle there was sludge on the bottom of the dipstick. I'm first priority was to service the transmission. The filters looked good, no sludge in the bottom of a clean drain bucket, and the fluid looked and smelled ok.
After service I had sludge on the bottom of the dipstick again. WTF!
Any moisture that cooks out of the transmission after sitting collects in the dipstick tube and create corrosion and sludge. Further proof that moisture from sitting is a bigger issue on these rigs than milage. Only 32k miles on a 20-30 year old rig might not be as significant as used regularly.
You can see the where the dipstick scrapes the side of the sludge in the tube!
The tube is fairly easy to remove and clean. Should have been the first step before dumping $250 worth of Transyn through it.