I have a grinding noise happening at around 80 mph. Driving down the highway once I get to about 80 mph it will start to make a grinding noise and you can feel a vibration on the floor shifter for the 4wd. Also it sounds like the speedometer makes the noise with it too. Last night driving home it started to do the same thing only at about 70-75mph now.

Any ideas on what this could be? Transfer Case?

The truck has 128000 miles on it. I had the rear end fully rebuilt in Sept. of 2006.

 

Oh yeah, it's a 2000 Dodge ram 1500 with the 5.9 liter. 4wd, quad cab, sport

 

what about fluid changes in the trans. case, and front diff? Also, are the wheel bearings okay?

 

never had fluids changed. front diff has never been touched either. If it was low on fluid would it grind? Why doesn't it do it all the time?

 

Anyone?

 

Sounds like the rear end is going again. Dodge says change diff fluid every 15K, and you should. Take it to a shop and get a good technician to go for a ride with you.

If not the diff, definitely drive train. Just check everything out.