I would get a rebuilt from the dealership if it were me and I think you need to shop around a bit more. When we shot our transmission replacement video, @infamousRNR was able to find a dealer in the California Bay Area willing to sell one for $2500. I can't imagine prices have gone up that much over the last few years.

I'm guessing you have an 01 or 02 model. The transmissions in these rigs are known to have an Overdrive Planetary Gear Bearing failure. When you drop the pan, you're going to see a whole lot of metal debris.

Whatever way you go, the video series we made will help you out with the swap. If you can do the work yourself, it's worth the risk to put a used one in. If you're going to have to pay someone to do the work for you, I recommend you drop the coin on a quality rebuild. Paying a shop twice for this job would be very expensive because your used one might be junk or not last you as long as you would have hoped. If you have the time, tools and space to the do the job yourself, I highly recommend you go that route. If you don't have a good set of tools, invest in some. They will pay for themselves very quickly. Shop labor rates are expensive. My local dealer now charges $200/hour. I don't know about you, but I don't make anywhere close to $200/hour. It's worth it to me to do my own work to save money and make sure the job was done right.

Here's Part 1 or our 3 Part Series: