Symptoms
The Sixth Circuit summarised the accounts as vehicles that "slip, buck, kick, jerk and harshly engage". The shudder is described as "a shake / shudder feeling that may be described as driving over rumble strips or rough pavement" — felt through the floor at a steady cruise rather than during a gearchange. The shift complaint is separate: hesitation or a lurch when pulling away or changing gear.
Likely cause
The complaint alleged two different mechanisms for the two symptoms: moisture absorbed into the transmission fluid behind the shudder, and the valve body behind the harsh shift. **These are the plaintiffs' allegations, not findings.** No court has ruled on whether either is correct, and this file does not treat them as settled.
How should it be checked?
Separate the two symptoms before spending anything, because they point at different places. A shudder at constant speed is the fluid question; a harsh engagement is the shift question. Ask what has already been tried — a fluid exchange is a common first move and its result is informative either way.
How can you check it yourself?
Drive at a steady 40–60 mph on a smooth road with light throttle — that is where the shudder shows and where rough tarmac would mask it. Separately, pull away gently from rest a few times and note any lurch. Confirm from the VIN which transmission the truck actually has before reading anything into either.
The question to ask the shop
Which transmission is in this truck, and has the fluid ever been exchanged — if so, when, with what, and did the shudder change afterwards? Has the valve body or torque converter been touched?