This started approx 4/10/2020. My driveway is on an incline to the house, and my Accord is parked outside on that incline. After a cold night, with temps around 32-degrees F, I drove to friends house. Auto would not shift from 2nd to 3rd. That trip went about 4 miles to my destination. When leaving, the car shifted perfectly. 4/11/2020, I took trip to local dump, also about 4 miles. While there, I shut off car, removed trash, then started, again. Shifting was normal through all 5 gears. I have an Actron CP-9690 scanner, and it read NO transmission codes, nor any codes on the engine. 'D' light did NOT flash any. I took it to the transmission shop that did the rebuild on it at 120,000 miles, after that trash dump trip, and they also did a scan, and found no codes, but did find a broken front motor mount. Said that they'd have to take out the transmission to check the shift-solenoids at a cost of $798 + tax + any additional repair costs, BUT, the amount would apply to the final bill. Ugh... I took the quote and left. The 10 mile drive home, shifted perfectly and smoothly.
I thought that maybe the mount could be causing the issue, so I had it replaced, yesterday, 4/14/2020. From the shop home, it shifted well, smoothly and strongly.
I took the car for a cold-weather drive, again, next morning (34-degrees F) 4/15/2020. Same issue: when cold, Positive shift from 1st to 2nd but no shift from 2nd to 3rd. I pulled into a local church parking lot, 1 mile from house. Shut off car for 15 seconds, restarted, and took off. Shifted smoothly through all 5 gears.
Anybody else have that? Would it be solenoids? I'm not totally frustrated, yet, but wife and I are about ready to sell the car if it's a huge repair cost. I've had Hondas since 1986, but this 7th generation has been a stressful experience, strictly because of the transmission.