GMC 2001 Yukon XL Owner's Manual page 26

Push and pull on the seat, making sure the support rod is
holding it firmly in place. Use the seat in this position
only when necessary for additional cargo space.
CAUTION:
If the support rod isn't properly engaged, the
folded third row seat could come loose in a
sudden stop or crash. That could cause injury to
people and damage to your vehicle. Always be
sure the support rod is properly engaged when
the third row seat is folded forward.
To return the seat to its seating position, push forward
on the seat and release the support lock rod. Secure the
support rod in its stored position on the underside of the
seat. Lower the seat to the floor and let the seat drop into
place. Lift up on the carrying handle to make sure the
seat is locked in place.
Return the seatback to the upright position by pulling
up on the release lever labeled 1 before the back can be
folded upright. Pull the seatback forward to make sure it
is locked into place.
Removing the Third Row Seat
Utility: If your vehicle has third row seating, it can be
taken out for more cargo space.
To remove the seat, fully open the rear doors and enter
the rear of the vehicle.
Fold the seatback forward
into the seat cushion by
using the lever labeled 1.
The seat cannot be
removed unless the
seatback is folded.
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