T7i focus shaking with EFS 17-55mm lens and with 70-300mm lens

[nimans]

I recently bought a (slightly used) EOS T7i to upgrade my previous T4i.  For some reason with the EFS 17-55mm lens and witht eh 70-300mm lens, the auto focus will shake and not finalize the focus.  I cannot take a picture because it's as if it's trying to find the focus point but shakes back and forth between focus points.  It also does this with the 70-300mm lens.  However it does not do this with the 18-135mm lens.  

I did not have this problem with the EOS T4i. I did check the lens metal contacts to make sure they are clean.  Can someone help figure out how to fix this? Thank you

[shadowsports]

Buying used gear can be good and bad.  Sometimes you save money, sometimes you inherit another's problems.  If you are going to have the lenses serviced, having the camera inspected might not be a bad idea either.