shudder like problem

[not you]

good morning or afternoon gentlemen and ladies or whom ever reads this.I been silent for a while giving everyone a break from me but it ends today. I have not been driving my truck my wife has for sometime now and i was with her yesterday and we where driving with noac at 2000rpm around 70mph and the truck started to shudder . I read some forums in here and some have described it as running over a wash board . My wife said the samething awhile ago butt when it comes to her she is very hard on vehicles and thats saying it nicely .some peopleon here stated it could be a torch converter locking and unlocking someone also said it could be a fluid issue (trans fluid) and to change the filter and such . it doesnt do all the time but she has stated it happen 2twice with her and i felt it yesterday . well thats a start what should i do thanks Shawn