Should I have the Toyota Dealer do a Full Flush of my Transmission?

Truck hasnt spent one minute in the dealer (or any shop) since I bought it outside of 2 warranty work items for TSB's.

You do you, but it makes no sense to risk a multi thousand dollar part that could leave you stranded because you didn't want to do simple maintenance every 60k miles....

 

I would just do a drain and fill yourself. It's pretty simple. And you can do this multiple times to achieve a full fluid flush if you want to. I had the dealer do a drain and fill 5000 miles ago and I'm about to do another one myself. A flush won't hurt at that mileage but honestly I don't think it's needed to keep your trans healthy for many many years. My dad's 2 Toyota trucks he's never touched the fluid in either and he's got 400,000 on both. I drive the T100 for work daily still.