Two problems related to frame rust have been reported for the 2004 Lexus GX470. The most recently reported issues are listed below.
Vehicle failed inspection due to rust hole in frame and transmission support. The mechanic said that the rest of the frame is in good condition which leads me to believe that it must be a defect with materials used for the frame, I would expect same type of damage to the rest of the frame. The car was well maintained, and it is in great condition otherwise, after close to 103,000 miles. This may be related to the Toyota frame rust issues that were reported since, to my knowledge the GX shares the same frame as other Toyota suvs/trucks. Lexus refused to help w/ the repair etc. And they deemed the vehicle unsafe to drive, I have to tow it out of their dealership. Attached, my shop review, Lexus review and pictures from my mechanic. I am asking Lexus for the pictures they took while the car was in shop.
Entire frame of the car is rusted to the point that almost nothing is holding the car together and we've been told it's not safe to drive. Has been maintained on regular basis and has always been parked in garage at night and on most weekdays. Car shouldn't be rusted out when cared for meticulously (documentation available).