1999 XJR

I have a 99 xjr that just yesterday decided not to forward. When I shifted into drive at a traffic light it jumped stopped and would not advance. Tried turning off and on but no go. I costed in N down to a repair shop (Van Ness Auto Service in Washington DC) and they said the transmission needs to be rebuilt. Otherwise the car has been flawless.

Any advise? on cost and where to go? Does anyone with a XJ use this place they claim to have a good mechanic trained at a local dealer.

Thanks

Rick