A warning light came on and I went to Advance Auto, the codes are P0700 and P1776
My van runs great and only has 49,000 miles
The transmission shop told me to go to the dealer?
Can you help me?

P0700 just indicates you have a fault in the transmission control system. P1776 (what is causing the P0700) indicates the low/reverse solenoid switch is sticking. I've read that many times the solenoid pack on the front of the tranny causes it. You can have it changed for around $300. That said, since you have no symptoms, I would just reset the light preferably using a scanner but you can also disconnect the negative battery cable for 2-3 minutes. If it comes back then you know it wasn't just a glitch. If it comes back the first thing to do is change the fluid and filter especially if it's been in there a while.

Thank you so very much