We have a 1998 Ram with the 24 valve diesel and automatic transmission in our company. We were extremely busy about 5 years ago and discovered that we hadn't changed the transmission fluid for about 100,000 miles. Our transmission shop recommended that we not change it since that might cause a failure. That was about 70,000 miles ago and the transmission is starting to have problems now. Should we go ahead and risk changing the fluid now or should we leave it alone? The truck has 200,000 miles on it. Or is it better to rebuild the transmission before there is a failure?