Battery issues with a Lexus 84 month Warranty Battery.
So I bought a used 2016 Lexus GX460. I have had it for two wonderful years and have never had an issue. The other morning I noticed my truck struggled to start for the first time. It was a muffled start that lasted 3-4 seconds before kicking on. It would start every time but I noticed that it would lag each time even after I drove for a little while.
I did some research and was hoping it was just the battery. I load tested the battery and it was not dead but was not coming back to charge at all. So I replaced the battery with one I got from costco, truck starts right up each time no lag now.
My question is that how would I go about checking into the warranty for the battery? Do I just go through a Lexus Service department? Also has anyone else experienced this on theirs? I tested the voltage after starting the car and it read 13.7V so I am guessing the alternator is good.
Edit: Battery is from 05/2022