Hi all—my new to me 1996 Dodge B3500 Pleasureway motorhome makes a noise that I can't figure. 318/5.2 engine runs strong and smooth with 59K miles on the clock. Trans shifts smoothly including the overdrive. At about 1500 RPM or 50-55 mph you hear a "whine". If you take your foot off the accelerator, the whine lessens, then returns when you put your foot back. The noise is not there before 50 or after you go above 60. Any ideas as to where to start looking for the problem?