I am just starting with the a new autopilot in a new New holland t7030. 

It is working well spreading lime, but occassionally, i find it wanders down the line.  Most times it's dead straight at 6mph.  Wander gets as high as 4" each side of the line.  It gets worse with speed.

Playing with the aggressiveness makes it wonder more aggressively.  I am running the aggressiveness at 50, the minimum setting.

I can rule out simple things like soil conditions, hydraulic flow.  

I see there are many settings i can play with.  I am wondering where to start.

I also wonder how much affect the cab suspension plays into this, as the antenna is on the roof.  Cab moves considerably with rough ground.

I am located west of Niagara Falls, Canada. 

Ken