Hi everyone. I have a 2014 silverado 1500 ltz z71 4x4 about 150k miles. The other day I drove home from work and all was fine. Left later and the truck started acting weird. Under normal acceleration at around 45mph the truck acts as it is shifting up and down constantly or going in and out of overdrive this also occurs cruising around 70. I have herd a slight whine type noise at the lower speeds when it happens. There is no slipping at start and no shaking. Shifts still seem smooth. I called a couple transmission shops and they said I need a new transmission. Does this seem right?