Rusty frames is not new to Toyota trucks. My first Truck was a brand new 86 Toyota 4x4 and I put 145,000 on it before someone crashed it for me and it had a lot of rust on the frame then I went out to find a used one and learned that frame rot goes back as far as 1979. I have owned over 20 Toyota trucks since I figured out that you can buy them drive them for a couple years and either make money or sell it for what you paid for it. I could not tell you how many I looked at where the frames were ready to break in half. I now see on other forums that the 01 to 04 have frame rot and even 2005 models with frame rot. Even Tundras have this problem. My question is why do some toyota have this and other do not? Not 4 Runners Not T-100s? I mostly buy the T100s and I have never seen any rust. Fords and Chevy I never see rust on the frame. I would love to buy a new Taco but I am not covinced they have fixed the root cause of there problem.

I believe The 4runner frames are manufactured in a different place than the toyots, i work at a toyota dealership in Maine and you wouldn't believe the the ones we see. toyota is now replacing frames on 2001-2004 tacos with bad rust. the only problems i have seen on tundra are the two frame crossmembers, the rear gas tank one and the one behind is rotting out, I have only seen on cracked tundra frame and this was due to the abuse from the rotted frame crossmember by the upper shock mount, not rust on the frame.

Yep, the frames are mfr'd in different places. I had asked Toyota about this for the Tacoma warranty extension that's sticky'd here; you can read their reply to me in that post.

Tacoma frames are made in USA, while 4runner frames are made in Japan.

To expand on that: Tacoma and Tundra frames (and entire vehicles) are made in the US, 4runner and T100 frames (and vehicles) are made in Japan.