06 Zetec Auto has hard gear shifting

[smote]

hey i've got an 06 Zetec Auto.
having trouble with the gear shifting.

when i turn the car on, put the brake on the move the gear shift to Drive, it is very hard. like its dragging on something.
also the same when moving to manual mode.
once in position it is ok. it is just moving between P, D, N etc..

i;ve tried the bypass switch but it is still the same.

seems like the solenoid is not fully working.

has anyone experienced this before?

i changed the rear calipers recently. would this have affected anything if it went wrong.

regards,
Luke