Delayed shift into overdrive (4th gear)
After shifting seamlessly through 1-3 gears, it takes the transmission about 15-20 seconds at 2500rpms, or roughly 55 mph to finally shift.
I took it to Certified Transmissions, and they ran the transmission through the gauntlet and determined it was definitely NOT a transmission issue.
Does anyone have any suggestions on where the issue may lie? Thanks for your input!