AWD fluid..at 50K is recommended by dealer..manual says to check it ?

Hello, Check usually indicates checking level, whereas replace means replace. Since they are likely not conducting a viscosity study for every vehicle that rolls in for the 50k service, I would say that checking would not involve replacement unless the fluid was obviously diluted, the transfer case was leaking, there were fragments found on the magnetic fill plug, or some other marker existed. The best place to contact when you have doubts about one dealer is Toyota/Lexus of North America, or at least a Lexus dealer which is not privately owned. The price is not outrageous, but I would wonder why it calls for checking when they want to replace it, too.