You were smart to not have the transmission flushed and to not trust the dealers opinion. It sounds like it could be the torque converter but I would have a transmission specialist drive it and see what they think. Also, you could find someone with a dealer level scan tool and have them see if there is any red flags in the live data.

why do you think it needs to be fixed?

@mountainmanjoe is right. Are you having issues currently? If so, please share as that is what we are here for. If not, I wouldn't worry about trying to predict the unpredictable future.

I have had the camry shudder while driving, it is happening at different speeds ( 40, 50, 65, 80 km/h ). Changed spark plugs and air filter did not solve anything and the shudder is getting more apparent as i drive. 

Saw a youtube video discribing this thing as a problem with the torque converter. So i talked to a transmission specialist and  they suggested i flush the transmission first to see if this will solve the problem,  (i didn't do it )

Instead, i made a mistake and called toyota dealership asking about 2012 2013 torque converter warranty , they wanted to check the car to determine the problem and came back saying i was right it is the torque problem and needs to be fixed and maybe along side with the transmission.

Note: neither my mechanic nor the transmission people drove/tested the car, it was all over the phone, only the dealership guys tested it, and i do not trust them fully and that is why i said i made a mistake.

Hey @mountainmanjoe

Still waiting for your opinion on the torque issue.

Thanks.

The Camry torque converter extended warranty applied to 2012 through 2014 models. The shudder feels just like driving over a "rumble strip". Supposedly you can drive for years with the shudder, but my daughter's 2012 Camry transmission failed within months of developing it. At about 137,000 miles.