i hear it too, but i knew it was the esp coming on. it sounds like an abs pump working.

 

Finally rained here so I was able to spin the tires and there was no "grinding" noise. Just some light clicking and the sound of the tires spinning (as much as the truck would let them with the traction control on). I do not believe I have the limited slip diff and I definitely don't have 4x4.

 

That's exactly what mine sounds like. A "pump" sound. It only happens when I am gradually applying power and its really slippery, and I have only heard it in reverse gear. I haven't heard it any other time. I have purposely spun the tires in forward and I didn't hear the sound. Of course the ESP light is on as well. I haven't tried to turn off the ESP and climb up a slippery slope. I will have to try that next time it snows to see if I hear the noise. I figured it was some system trying to correct the tire spin issue so I didn't think it was a problem. I wasn't even going to try and take it to my dealer since they are clueless to the 2009 Rams functions.

I hope that it doesn't snow anytime soon though. I'm ready for spring!

 

Yes it is ESP kicking in. I have much experience up here in Minnesota with all the snow. Every time my truck does it the traction control light flashes and if the headlights are on you can see the lights dim like when ABS modulates the brakes. I have driven many cars with traction control and I would say about half of them do make some sort of the noise from modulating the brakes to control wheel spin.

If it bothers you just disable ESP and the noise is gone, but be ready to react to oversteer.