My truck @ 120K developed a tendency to have severe shudder under light acceleration while traveling at 50mph+. This is especially prevalent when going up a slow incline. While the shudder is occurring, a light press of the brake pedal will immediately stop it.
If I disable overdrive, the shudder doesn't occur. So I think the shudder is occurring while in overdrive or when truck is trying to go into overdrive.
What exactly is the role of the torque converter as related to overdrive? Does it try to lock-up when going into overdrive? How is that action related to me applying a load on the engine?