AC60F 6sp auto stuttering on highway?

Good afternoon TW,

recently i have been experiencing this very slight/miniscule stutter but i cannot for the life of me figure out if its the truck doing some typical 3rd gen auto clunkery or if my torque converter/friction plates are slipping. This is not the same as gear hunting which im very familiar with. It is also unrelated to the higher 'stall' in 5th when needing slightly more acceleration as it happens when the RPMs are constant @ approx 68 MPH

To describe it it feels like the TC is unlocking and relocking especially in 5th or 6th. It feels really similar to when you depress the clutch in a stickshift and let out and get slight chatter as it catches. It really isn't enough to call it an issue but it is a bit concerning.

Some recent changes and events leading up to it:
1. Fluid change with ATF-WS 5k miles ago, drain, fill, drive 3x with NO thermostat bypass used.
2. accidentally dumped it into 1st from rolling back in N while in 4lo at a speed lower than 1 mph (being jerked around during a recovery attempt as dumb me had my hand resting on the shifter like an idiot) truck drove fine 3k miles since then. However its worth considering for an issue like this
3. added 33 inch tires
4. Temps being monitored the truck likes to sit at 190F-210F on the highway

Where do i start to address this? or do i drive it til something fails. Im contemplating a fluid level check WITH the thermostat/cooler bypass. Any insight is appreciated.

 

What is RPM?
Does shudder disappear when releasing the accelerator?
There are 3 stages of the torque converter state.
-Fluid coupling (lockup cluth is not active
-Partial (lockup clutch is applied based on PWM signal)
-Fully locked.
Releasing the accelerator allow the torque converter to go to Partial state. Locks up as soon as accelerator is applied.
Typical shudder happens when the torque converter is fully locked and rpms below 2K

OEM ECU calibration does not unlock the torque converter in 5 and 6. It locks it right after the shift to those gears.

Solution is to seek a tune or use S mode to lower the gear to bearing RPMs up

 

2000 rpm in 5th @ 68-70
I get it in S mode 4th as well @3000 rpm
Its typically just one ‘pulse’ every now and then

 

Happens while driving over hills?

 

Yup, hills or acceleration. It honestly feels similar to a slight misfire

 

Yeah, this is typical normal behavior.
Tunes do help to increase the throttle limits to overcome this, but wont eliminate it completely.
I still have it under a certain conditions under the load.