Thought 5R110 was slipping - now not sure
So I was driving through town a week ago - in gear - 30mph - steady, and my RPM's rose up 500rpm then settled back down. Then a few days later -driving through town, stopped at stop sign, went to pull away and RPM's rose up a thousand or so and I knew right away that wasnt right - took my foot off the gas - let it settle back down, and tried it again - was a small jerk and the truck took off like normal. Drove through 3 other stop signs no problems.
Turned around, drove home and called (new) mechanic. He picked it up on Friday, drove it on Monday - no problems. He said it seemed odd that there is a trans problem because it shifts so smoothly. He was going to put it on a lift today, drop the pan and start troubleshooting. He said might be a sticking valve?
Trans is stock with 219,900 miles. Fluids kept changed along with filters. No other problems ever with the trans.