Scraper is “washboarding”.

Symptoms:

Scraper causes a washboard effect.

A-If washboarding is close together, flow rate is too high.

B- If washboarding is far apart, flow rate is too low.

Cause:

• SCV flow rate is set too high or too low.
• Washboarding can occur when the blade is at an overly aggressive angle (construction model scrapers have a more aggressive angle while 'finishing' scrapers do not).
• It can occur when the ground is hard and has not been prepped for dirt moving.
• It can also occur when the tires' air pressure on the scraper does not match (one is lower than the other). 
• It can also occur if the scraper has split hydraulics and the cylinders controlling height over the right and left walking tandem are not equally pressurized (one cylinder may have a leak). 
• It can also occur if the tractor hitch is mounted to the scraper drawbar too high or too low.

Solutions:

Decrease or increase the SCV flow rate. If still present, adjust counterbalance valve pressure.

Contact implement service provider.