Intermittent shutter, possible transmission issue

Hey guys,

2010 4.6L 4x4 V8

I am experiencing a slight shudder under light acceleration between 30 and 40mph, right before switching into a higher gear (I believe 4th).
According to the previous owner, this is quite consistent with a problem he ran into when he had to get the transmission replaced at 109k miles. The truck has now 159k.
I am not always able to replicate the issue under the same conditions which I'm guessing will make the diagnosis difficult. It seems to usually happen when the transmission is not completely warmed up.
If it is indeed the transmission, I assume I would be out of luck in terms of warranty on the part that was put in 50k miles ago?
It was done at a Toyota dealership in another state.

Right now my plan is to bring it to my local mechanic and get a transmission fluid check to start with.

 

For anyone wondering, brought the truck to my local mechanic. As expected, I couldn't replicate the symptoms, especially with the transmission warmed up. They took a small sample of trans fluid and it didn't look bad. I will be dropping it off again for a full transmission drain and refill and they'll be inspecting the pan as well.

 

Keep us posted on the outcome!