I have a new RV with about 2500 miles. Sometimes there is a noise like the transmission is slipping, but the RPMs do not show an increase. This has happened going down the road but seems to happen more when taking off from a stand still. I read in the manual, that if you hear this, it is not the transmission slipping but is the electric fans kicking on. I do not think it has been hot enough so far this season to have the fans kicking and one time within ten minutes of starting my drive. The temp gauge is not showing that the motor is heating up. It is a 05 Challenger with the W22 Workhourse chassis. 8.1L with Allison. Anyone else experience this, or should I ask Workhorse? Sure is noisy.