I bought a used 4010 and have had it a couple months now with no issues or problems. Recently I have used it to pull a stalled vehicle about 30 feet and pull out a stuck vehicle. Both times I put it in 4wd and locked differentials. After each occasion while driving the unit it feels as though the park brake is engaged and is very sluggish and loss of power. I have double checked the diff and 4wd as well as engage and disengage the brake in case it was dragging or slightly engaged, everything seems dime there. Any ideas why it would do this or what is causing it ? Any help would be greatly appreciated