Ultra low loader operating pressure is too low. The reasons are:
(1) gearbox oil pan oil shortage;
(2) ultra low loader main oil spill;
(3) ultra low loader gearbox filter clogged;
(4) steering pump (or hydraulic pump) damage, resulting in serious internal leakage;
(5) gearbox regulator pressure adjustment is not appropriate;
(6) Suspension pressure valve spring failure or break