GMC TopKick 2007 Owner's Manual page 11

The recline lever is located on the outboard side
of the driver's and passenger's seat cushions.
To recline the seatback, do the following:
1. Lift the recline lever.
2. Move the seatback to the desired position,
then release the lever to lock the seatback
in place.
3. Push and pull on the seatback to make sure it
is locked.
To return the seatback to an upright position, do
the following:
1. Lift the lever fully without applying pressure to
the seatback and the seatback will return to
the upright position.
2. Push and pull on the seatback to make sure it
is locked.
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