I am looking for help on a 1964 D6B 44a10764 dozer I have done all required maint. However it still has the same problem before and after. I am not sure if it is the operator or a mechanical problem. 1) The problem is it want pull up a grade of any sort or push a pine cone. So I am thinking I am not putting in it in low gear or its the clutch. any help would be great and much appreciated. I have no manuals and its very hard to find any info so I joined this group hoping to find some help.