In the upper area where the final drive bolts to the frame there is a lock nut (large) I don't remember the size, (over 1") It's on the front upper part of the final drive bolt circle. You loosen the lock nut and tighten the inside bolt, (3/4) I think. There should be several threads remaining or you need to change the brake lining. You don't want to run the brake all the way to the end otherwise it's metal to metal and the metal goes in all the rear end parts.
Hope this helps. I know Dressers some, D38E should be the same as a TD8-H.