Have a 1981 D5B dozer that was working perfect, then the transmission cooler went out . As you know the transmission filled up with coolant. We got the cooler replaced and flush the transmission fluid, finially got 98% of the water out, fluid is not perfect but good. Now that that issue is fixed , now it will run perfect for sometimes 4 hrs then it will just come to a very slow crawl. I can shut it down to a low idle and give it about a minute or so then it will go again, but not for long, maybe 30 minutes. What could be going on ? I have changed both filters multiple times to insure they are not clogged. Please guide me, before I call cat out to do something simple to fix it..