Lexus RX Transmission Problems

stever

This article may help, especially since you've been a "loyal" customer although it sounds like the dealer may be more interested in selling you a new Lexus:

The Secret Warranty

You don't mention the year, but you are pretty far along in miles. But it doesn't hurt to ask Lexus if they'll assist with the replacement.

la4mead

That dealer has not been doing you any favors, but they are glad to take as much of your money as they can drain from you. $8000 to repair the transmission is a complete joke... I doubt you are laughing the same as they are. Whoever told you that deserves a reprimand. First, dealers don't usually include transmission service as part of their dealer service until failure, the owner must specifically ask for it. Check your records.
Being a firm believer in preventive transmission maintenance because I keep my cars "like new" a long time, I've had more than one dealer refuse to do any more than "power flush" the transmission fluid mechanically, a high-profit but questionable maintenance practice. I've had to go elsewhere for transmission service. By "the book" is none until failure, then after failure, they are quoting you a figure that is irrationally high to encourage you to trade-in. The game they are playing is totally bogus.
The next step is for the dealer to bargain down the cost of a quality rebuilt transmission *which must include all updates* to more normal amount in the range of about $3500 (perhaps less) based on what others have been paying. You can check on Club Lexus or Lexus Owners Club forums to see the costs and how other owners found quality rebuilt transmission repairs. Lastly, regardless of dealer's recommendations, have the transmission serviced annually.
Take a look at this forum thread (use the "search" function) to find how other owners successfully negotiated with Lexus for help on the cost. Keep in mind these thread postings are generally complaints, which represent a tiny percentage of all RX300 ownership experience.
I wish you good luck, and I hope you will share what happens when you speak with the dealer, Lexus, and what happens thereafter.