Pontiac Montana SV6 2008 Owner's Manual page 62

2. If the child restraint manufacturer recommends that
the top tether be attached, attach and tighten the
top tether to the top tether anchor, if equipped.
Refer to the child restraint instructions and
the following steps:
2.1. Find the top tether anchor.
2.2. Route, attach, and tighten the top tether
according to your child restraint instructions
and the following instructions:
1-58
If the position you are
using does not have a
headrest or head restraint
and you are using a
single tether, route the
tether over the seatback.
If the position you are using
does not have a headrest
or head restraint and you
are using a dual tether,
route the tether over the
seatback.
If the position you are using
has an adjustable headrest
or head restraint and you
are using a dual tether,
route the tether around the
headrest or head restraint.