first off, welcome. i take it that this nt nb3500c is the renamed yucchi dozer sold by northern tools as the nortrac brand? 30hp diesel engine with 3ph and rear pto? the only help i got is northern tools phone number in minnesota, usa.= 1-800-533-5545 or nortrac directly 1-800-521-0438. if you get through, ask for "bob" in the nortrac parts dept. he was helpful when i talked with them before. there are some others here that own that dozer. maybe they chime in. also try northern tools website. northerntool.com good luck.