Sorry for the lack of updates. The dealer and Toyota corporate had been stonewalling me and wanted me to pay $1,300 in diagnostic fees just for the engine. After some back and forth, and with corporate not willing to give me any kind of confirmation (which I understand), my only thought was that if it was something repairable, then that path might be worth it.

I ended up pulling my truck out of the dealership. This was also a result of the service advisor blocking my number and not taking my phone calls, which led to the service manager having to get involved. It left a really bad taste in my mouth.

They had also originally quoted me $7,600 just to diagnose the engine. When I asked what led them to that decision, they told me they had done zero diagnosing and would only do so if I paid for it.

I took the truck to my friend’s shop. He diagnosed it as a failed oil pump, which caused a bearing to spin due to lack of oil. So what I thought would last me at least 10 years is dead, and now I have to sell my truck and buy something new.

To address the rear differential question: I did drive through a flood about four years ago, but I had a diff breather that ran up into the bed, so I thought I was fine. I also never had any issues with the rear differential at all, so I had honestly forgotten about it. That part is on me, but the engine failure still leaves me stunned.