I have a 1993 Suburban, 1/2 ton 4WD with the 4L60E transmission. In 4th gear, overdrive, under load the transmission will shudder. If you press the brake pedal lightly or shift out of overdrive the shudder will quit. Other than that the transmission works fine, I don't notice any slipping. Fluid and filter was changed about 15K miles ago. I have heard that it could be either the TCC solenoid, TPS solenoid, a worn valve body, or even the torque convertor itself. Has anyone have experience with this or any thoughts or ideas? I just don't want to replace parts that I don't have to. Thanks for any advice!!