I bought recently a TD8E. I believe it is a 1975 model. It was in some mud and the left track seemingly wouldn't do anything. I got it out of the mud and drove it down to the yard. Now, I got the tracks all cleaned off and it seems it's the right track that won't do anything......what that means is I can used the left track (backwards and forwards) to steer it, but when I pull back on the right track lever it seems as if the dozer just stops, seems as if there is a slight tightening of the right track but it doesn't turn at all. Is this a brake issue or does this dozer have clutches? Any help would be most appreciated.