transmission problem

I have a 91dodge 250pickup with a cummins turbo diesel the trans is an 46rh it lately has been shifting in and out of overdrive for no apperant reason. I was told by a dealer that it could be the pressure solenoid located above the valve body. I have changed the filter and fluid but it still shifts in and out of O.D. with out requiring down shifting. :banghead:
bobturbo

Get A New Sylinoid. Problem Fixed