Milesjohn696

I've got an 2008 A4 and I'm having some issues with the triptonic transmission.Here is the problem when I put it into drive it will not change gears on its on I have to use the steering wheel shifters to shift gears.Every other one works fine.S works shifts on its own.When I put it into D or switch it over to the manual there's no difference.Just will not change gears on its own in drive.I haven't tried anything yet to correct the problem was hoping to find some answers here.Thanks for your help.