Toyota Tundra Transmission Problem

Okay, it's a 2000 automatic V8 with approx 78k miles. It's been running fine up until yesterday. I get to a stop light and the truck goes into low idle and then dies. It starts right up in park or neutral but when I shift it to drive or reverse or the low gears, it dies. To be specific, it lurches a little and then dies. I have it towed to my house. This morning I start it up fine. I put it in drive and the truck shifts into gear and the engine is fine. I get to my destination (20 miles of freeway driving later) and I get to a stop sign and the same thing happens again. The engine dies. So i'm thinking when the engine is cold, it's okay, after its been running awhile this problem arises.

I have it towed to a repair facility. I don't know anything about this place because I'm 20 miles from home. They run diagnostics and then later tell me I need to have the transmission replaced. They give me a quote of $4700!! Does this sound right?!?!

Thanks :shock: