Trans shudder

Hello all first post here
i have an 08 tundra 4.0l 2wd - it was a my old mans truck that he left to me

i have the shudder coming from what i think is the torque converter, from what i have read it is somewhat common, i am going to replace it however the issue i am having is that is seems to be a sealed trans. i want to do a complete service to it filter, fluid etc.. my question is this
how do i tell if its full of oil and or is there a service manual with a procedure for this operation
thank you in advance

 

There are some vids here on how to do the fluid exchange, its about 16qts... If you will be dropping the pan, buy all the bolts ahead of time... I've heard they will snap in there and will need to be extracted... There is a level bolt that will need to be removed, but its a process as well.. Ensure if you have tow package or not, since they may be slightly different