07Sport Quadcab
Member
Vehicle: 2007 5.7 Hemi with MDS, 545RFE transmission.
My tach indicates quite a variety of RPMs at a steady 60 mph (5th gear as far as I can tell). I will notice it showing about 2100 at times, and at other times it may be 1900 or even 1750. I've never felt or heard any change in engine speed , but with road noise it would be difficult to detect anyway. There doesn't seem to be any correlation to hills; I'm talking level highway conditions.
Is it possible this is the MDS kicking on and off? Some posters talk as if they know when it's active or not active; how can you tell? I'm fairly new to this truck, but I've not noticed a change in sound or by seat of the pants that would tell me it's on or off.
I assume the 545 has variable line pressure- can that cause the clutch to slip a little at times?
My tach indicates quite a variety of RPMs at a steady 60 mph (5th gear as far as I can tell). I will notice it showing about 2100 at times, and at other times it may be 1900 or even 1750. I've never felt or heard any change in engine speed , but with road noise it would be difficult to detect anyway. There doesn't seem to be any correlation to hills; I'm talking level highway conditions.
Is it possible this is the MDS kicking on and off? Some posters talk as if they know when it's active or not active; how can you tell? I'm fairly new to this truck, but I've not noticed a change in sound or by seat of the pants that would tell me it's on or off.
I assume the 545 has variable line pressure- can that cause the clutch to slip a little at times?