Yikes - I thought a FF'ing instalation in DH's truck was going to be simple. However, according to the trucks manual the top tether anchor is threaded through a loop of fabric behind the seat and then attached to the next nearest tether point (so for an outboard passenget seat it would be the centre tether anchor). However, the Marathon tether strap comes out from either side of the back of the seat so it is off centre when you loop it through and then attach. We can not get it tight enough, nor would it work to just attach it to the anchor right behind the seat. Any tips on getting it tighter or is this seat just not going to work FF'ing in DH's truck?