1995 Chevy Suburban V8 Four Wheel Drive Automatic 197, 00 miles
The transmission shifts through all the gears just fine, but when it should shift into overdrive, the engine just continues to rev. If I let off of the gas to below 2000 rpm it will shift, then I can continue driving as normal. What should I do first? Last year I had the Dealer service the transmission. They replaced the oil and filter and I believe they flushed it as well.