Actually, running the wheels when in the air is the same as taking off very lightly. You're describing what happens when the clutch plates are badly worn. They slip under normal load but not when under very light load. The additional clue is that reverse still works. Line pressure for the fluid that hydraulically applies the clutch packs goes very much higher in reverse. That holds those clutch plates from slipping. A transmission specialist may elect to perform some verification pressure tests, but most likely it's time to rebuild the transmission.
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Monday, February 20th, 2017 AT 5:20 PM