re 2008 rx350 - are there any issues with diff

I would say it's a wheel bearing only from experience. I have seen alot of wheel bearings fail on rx330's and 350's. I have never seen a differential fail or make a humming to this day. idk if towing would have necessarily been a factor, the bearings just tend to fail with time from what ive seen

Good day Kyle, Many thanks for the quick response. One thing I inadvertently omitted - the humming noise stops the instant I take my foot off the loud pedal and reappears as soon as I put the foot back on. The noise seems to be kind of "central", it is not coming from any particular direction.

If you have an exhaust gasket that is rotting away, that may be the potential problem. When the gasket fails, it allows exhaust gases to exit the system creating excessive noise since it's not reaching the muffler. I have seen exhausts leaks a few times. It's all just a guess since I can't physically see and drive the car.

Checked out the exhaust and it all OK, thanks for that. Dealer tells me that they are going to replace crown wheel and pinion - waiting for service date.

Hi Kyle, Got my car back from the dealer - they have replaced the crown wheel and pinion - the noise has gone - car is now super quiet. FYI they had to drop the engine to do the work.

Absolutely. I've pulled plenty of them. You can either pull the engine and trans and then separate the engine to get to the items or pull the trans and from differential/transfer case and do it that way. To each its own.

Humming noise is back - car had only done about 5 to 6k since new crown wheel and pinion. Dealer inspected car and I was told "normal noise for that car". Subsequently took it back another two times and the last time the Lexus field rep was involved and got I the same answer "normal noise for that car". Begs the question - if a brand new car demonstrated that noise what would be the outcome. Struggle to believe that a Lexus has a built in noise, if it had been there at test drive I wouldn't have touched it..

I got 2008 RX350 AWD and humming noise coming from rear end, any comments or suggestion ?

Same here, at first was told wheel bearing, then was told differential. then dont know what to do now. apparently differential is hard to fix.