2005 Toyota Tundra rumble strip shudder, now Check Engine code Torque Converter P2757

Right up front, we are not mechanics, so please explain any suggestions in language (preferably without abbreviations) that’s as simple as possible. Thanks!
We’ve got a 2005 Tundra SR5, automatic V-8 with 4X4 that we bought used 4 years ago with 45K miles on it. The truck has been seldom used and how has only 49K. (Not a typo!) Sometime last year, we began to feel the so-called “rumble strip” shudder between 30 and 40 mph, which does indeed feel like traveling over rumble strips. At that time, we had no warning lights appearing. We continued to drive the truck, literally only about once a month, and the rumble strip issue continued until recently. Now the shifting feels pretty rough at those same speeds, but we’re not actually feeling the shudder like before. However, the Check Engine light has come on. An auto parts store scanner detected the P2757 code, which the printout says is the Torque Converter Clutch Pressure Control Solenoid Control Circuit Performance or Stuck Off. I’ve spent literally days online researching the rumble strip issue, and now trying to find out more about how to best deal with the code.
Other threads (mostly for Tacomas and 4Runners) have indicated possible solutions for the rumble strip issue include full automatic transmission fluid exchange or repeated drain and refills. There seemed to be debate regarding flush/drain/full exchange, and also whether to use the WS fluid or some other brands/viscosity of fluid. And others tried using an additive called Dr. Tranny Shudder Fixx. Some other posters actually replaced the torque converter, of course a very expensive deal. We are assuming that the rumble strip issue is directly tied to the P2757 code, but actually couldn’t find much info about others stating that this particular code was detected.
Our questions:
Is it safe to assume that the rumble strip shudder and now the torque converter code are indeed related?
Now that we can’t actually feel the rumble/shudder and the P2757 code has been detected, does that mean the condition has worsened in terms of being more likely to need a new torque converter?
Is this a safety issue, in that we should not be driving the truck?
Could we damage the transmission if it’s driven?
Should we only take the truck to a Toyota dealership vs. our local mechanic?
What would you try first?
If we can provide more info about our situation that would assist with anyone making suggestions, please let us know. Any recommendations would be greatly appreciated! Thank you in advance!

Rumble strip shudder normally at that speed is torque converter failing or not operating correctly. The code confirms it.

I would drain refill fluid and add the Dr Tranny Shudder fixx ($10) as a good measure.

Hope for the best!

And clean or change filter if applicable.

I’m not an advocate of additives for a vehicle that one intends to keep for a long time. The best solution, since you’re admittedly not mechanics, is to first carefully follow the directions in your owner’s manual and be sure it has the correct amount of fluid, then take it to a reputable independent tranny shop for a look-see.

If the tranny fluid is low and adding fluid stops the shudder, I still recommend getting it to a shop. And when you check the fluid level follow your owner’s manual instructions TO THE LETTER. Different vehicles use different protocols for this. Toyota typically requires that the tranny be at operating temperature, the engine running, and the shifter be cycled through the gears, but do not take my word for it… check the manual.

+1 for all comments made so far.

Thank you all for your comments and suggestions. As of start-up today, the Check Engine light is no longer lit(!), and as I stated in my original post, we are not currently feeling the rumble strip shudder either. Today, we actually dropped off the truck in for its annual Pennsylvania inspection, and left a note to make the mechanic aware of the intermittent warning light and P2757 code of just a few days ago. So I suppose we can call in tomorrow while the inspection is going on, at least to have them check the transmission fluid level. This is not at a dealership, but our local mechanic, so sounds quite touchy and like there’s no certainly they’ll know exactly how to check the fluid level. There’s only one tranny shop in town, but we’ve no references to know if their work is really reputable. Hmm…and when we contacted the Toyota dealership service techs when the shudder started last year, they seemed to have no idea to what we were referring, even though the rumble strip shudder seems to have been fairly common (at least all over the internet)with Tundras. – Not exactly inspiring confidence at the dealership either! Yikes! What to do?

I’d have the filter changed, the pan cleaned, and the fluid exchanged and go from there.

Fords have been prone to this problem for years and it’s quite common to get that rumble strip vibration with aged fluid. In some very extreme cases a new converter may be needed but it’s not that common.

I can usually tell when the fluid in my Fords need to be changed. Around the 35k miles mark if I allow it to go that long they usually develop a subtle shift flair and random balk. Left unattended, this eventually turns into a rumble strip shudder at around 40 MPH. A fluid change has never failed to cure it.

Other than that…