I would keep playing with your heading number - adjust it 5 or 10 points at a time, until you find the sweet spot. Since your rows are straight I would say your tracking number should be good. It is easier if you work on one setting at a time when dialing in an ATU. Personally, I would also probabally have the steering wheel speed set higher, I assume you slowed it down to counter act the violent "s"ing - so you may want to tweak this after you get the heading working properly.

If you dont have the additional manual for the ATU, you should take a look at it. It steps you though the symptoms and what to change for each of them. Your dealer should have it or you can download it here http://stellarsupport.deere.com/en_US/support/AutoTrac_Universal.ht...