2001 Isuzu Trooper Transmission Shudder

myth1_

I own a 2001 Trooper S. Recently the automatic transmission has developed a shudder when in the overdrive gear. This is the highest gear the the truck shifts into when underway It feels like a manual clutch shudder might feel like it as if its trying to grab onto the gear and shudders for a few seconds until I let off the gas and drive with a light foot. The transmission shifts and runs fine like new in the lower 4 gears. No tranny fluid is leaking that I am aware of. That is I don't find any on the driveway. I believe that the Trooper uses a torque converter lockup overdrive gear if I am correct. Not sure about that. At first the shudder only happened under medium to hard acceleration. If I took it easy on the gas it didn't shudder. Now in the last couple days it seems to be doing it more and more even when normally driving, it seems to be shuddering or even slipping. I have had a couple suggestions from motor head friends. One is that the torque converter needs to be replaced. Another friend said it might be computer programming that is causing the shudder. The truck has about 87,000 miles on it. Other than the shudder, it is running very well. Have any of you Trooper owners experienced this? What was the problem and what was the fix?