I replaced the battery on my 2001 LX470 37 months ago with a new Lexus battery that I purchased from the local Lexus dealership. This Easter morning while driving from Ohio to North Carolina, the car began to stop every 20 seconds or so but restart itself immediately. I thought continued driving in this condition could not be good, but also thought stopping might mean not being able to restart along I-77 in 30 degree weather. Long story short, by using my GPS with points-of-interest, I found an AutoZone open with the proper battery in stock (it gives phone numbers as well as locations). The GPS pointed me in the right direction, I got a new battery, and was on my way.
Took the old battery to the local Lexus dealer to discuss only getting 37 months on an 84-month warranty battery. At 37 months, their warranty only provided a $50+ credit against the purchase of a new battery FROM LEXUS. That was impossible for me to do on an Easter Sunday morning.
I just wanted to point out to you all how useless the Lexus battery warranty could be if a Lexus dealer is not near or not open. The battery itself might be a good battery, as I was told, although my experience does not bear this out. But be wary of the warranty.
After some complaint, the dealership gave me a $50+ credit against future work done at their service department. You might need to do the same.