On the subject and FWIW, my neighbor's son has a '01 LX470 (same engine as GX, of course), and he just changed his timing belt for the first time at a little over 150K miles. The belt still looked good. It had a small section that was begining to show enough fatigue that would make you want to replace it.

 

The recommended 90k miles is just that a recommendation. My buddy has a 03 GX470 with 135k on it still has factory timing belt. It's one of those things-some people are lucky some not so much.

 

There is a Drive Chain which is within the Transmission which is covered under the Powertrain warranty. Hope that is not what you are asking.

 

On some cars, the failure (breaking) of the timing belt causes significant engine damage, such as the destruction of the valves as the pistons and the valves move out of sequence. Other engines are what is referred to as "freewheeling". Does anyone know if the 2007 GX-470 is freewheeling or not? Thanks.

 

I believe on Toyota a timing belt failure is not catastrophic, as opposed to when I had an Audi I was warned to have that belt done on time because the results would not be good if it failed.

 

From what I've read the 4.7 is an interference engine. I believe that the belt also controls the cam(s) which means the valve train would stop moving but the bottom end would continue with catastrophic consequences.
Please correct me if I'm wrong.

 

This is one area where the risk of not doing the full service (timing belt, water pump, and seals) at 90k, is not worth the reward. Although it is not cheap, the dealer documentation on a benchmark service like this one has value in peace of mind and resale. IMHO
Unless you have complete confidence in you doing the job, don't attempt the job.

 

This used to be the case, but not with the 1UZ/2UZ V8. It is an interference engine, as are all the V6 engines with VVT-i. Going much more than 90K on a timing belt is a severe gamble.

 

I stand corrected
Lexus

2.5L Non-Interference
3.0L V6 Non-Interference
3.3L V6 Non-Interference
3.0L Inline 6 (1992-97) Non-Interference
3.0L Inline 6 VVT-i (1998-2006) Interference
4.0L Interference
4.3L Interference
4.7L Interference