Dig servo problem

[250cows]

My dig servo (hitec 225mg) will ease backwards and eventually disengage my 4wd when you operate the reverse throttle triger, (the more I push the reverse throttle triger -- the more the dig servo will move rearward). Then when I engage the the dig, it works fine until you turn left then it eventually disengages the the dig (the more you turn left -- the more the dig servo will move foward).
Its a new servo, I put on a new 3000 receiver. I'm running a spektrum dx3.0 radio, and have played with EPA's, & running 2s lipo's . I've tried seperating ALL wires to eliminate interference.
Any help would would be appreciated.