I have a new DD3600 southbend clutch. It has a hard time going into 1st and reverse. Grinding gears or truck jolting when it goes in. I installed a hydraulic assist in hopes of curing the issue. The pedal is adjusted and the floor mat is not an issue. I have put about 500 miles on the clutch in hopes of breaking it in but no resolve. What may cause this issue and and tricks to fix it?