My 2008 Rx 350 my mechanic says the timing belt seal is shot- that It's a mfg issue and $5,000 to repair. Any one else aware of this?

The 2008 Lexus RX 350s don't have timing belts -- they have chains. The change from timing belts to chains began with the 2007 Lexus RX350s. I had a used car dealership try to sell me a 2009 RX350 and it was close to 100k miles and I wanted to know how much that maintenance cost and what all was done to negotiate that into the price. They told me several times they would replace the timing belt and do all these other things at that 100k mile mark and charge me a reduced rate of $500-600. I went to the Lexus dealership to get prices on maintenance so I could understand how it fared to other luxury SUVs and happened to ask about the services and how often they are done and what's done at the 100k service and how much the dealership charged (which is always high compared to a reputable mechanic) and they verified the chains are NOT on the models starting with the 2007 edition, major services are every 30k miles and they charge around $700 (not the $1500 the used car dealership told me to expect if I took it there versus Lexus) and the others are oil changes every 10k miles or 12 months ($130) if I recall correctly on the oil change mileage - it's either 7500 or 10k but thinking the latter be the used car place told me 7500 and they would also do that for me but they recommended I do it at every 5k (which I also remember wasn't true and felt completely pissed off and betrayed in that I typically don't trust people and especially not a used car salesman because of all the crap they have tried to pull on me because they assume I'm a female and therefore less knowledgeable about cars and try to exploit that). I has told that man about my experiences thus far and how awful and frustrating it had been and how I thoroughly research these things and felt that given I had told him this he wouldn't be stupid enough to try that on me but I was wrong. I trusted him and was lied to. Just like I'm going to find another salesman at a dealership, I would recommend you find a trustworthy mechanic. The timing belts are so expensive to work on in any capacity and any mechanic trying to tell you they're going to work on anything to do with a timing belt on your Lexus is blatantly lying to you and pocketing that money.