overdrive jumping in and out
I have a 99 ram 2500, 24 valve desiel, auto trans. At 45 mph the whole vehicle surges, acting like it is jumping in and out of overdrive. it does this usually when cruising, not when underload or accelerting rapidly up to highway speed. It only last untill the truck hits 52-55 mph then runs normally, and does not ever do this when the overdrive is off. I have never worked on an auto trans so am at a loss at to what could be causing me this problem.