Lexus GX470 under vehicle noise

[mweston]

When trying to accelerate rapidly, there is a loud clunking noise that sounds like it is coming from under the right front seat. It feels like the AWD or transmission is not engaging properly. This does not happen every time but frequently. If I accelerate gently, it does not occur. We have only had the vehicle for a couple of months. When we purchased it from our mechanic, he had disable the electronic suspension system (it had failed in the past) and replaced with mechanical springs and struts. AWD is permanently "on" as far as I know.

 

Thanks

Mike

[mweston]

My mechanic thinks it's the transfer case, which is under warranty. Should the vehicle not be driven at all until the case is repaired?

 

[Lexus Owners Club]

It does sound like either the exhaust system knocking against the underside (maybe loose mount) or otherwise and engine or transmission mount is weak and allowing too much flex on the motor on acceleration