Mechanical play in Yukon passenger seat

[Bill1944]

Help!

I have a 2000 Yukon that has a good deal of mechanical play in the front passenger seat back--that is front to back play . I've tracked it down to a spring-loaded electric adjuster shaft. If you adjust the seat to it's furtherest adjustment it doesn't do it then( I think at that point it's jammed).
When you stop or start off you feel the seat bump- it doesn't bother me because most of the time I'm driving but the wife(THE BOSS) who normally rides "shotgun" complains about it!
Is there any mechanical adjustment to take out the play? The dealership told me I'd have to spend megabucks to get it fixed.

Thanks for any help!
Bill1944