05 isx cm870 chugging and surging baddly

[ncdodgeman20]

hey everyone new member here i just bought a used 04 kenworth t800 dump truck it has an 05 isx cm 870 which has started giving trouble when i first got it we serviced it and ran overhead on it but now it is chugging and surging when the motor gets under a good load like going up hill or fully loaded and give throttle around 3/4 to full its trowing fault codes 2182 6418 engine brake actuator driver 1 circuit. since the code i replaced the #1 exhaust brake solenoid but nutthing changed and once you clear the code while driving the secound the jakes engage the code comes right back any help would be great i will try to get a video one what it sounds like   


https://www.youtube.com/watch?v=dgUYIlgVtWM
dont know how to post the link