take it back to the dealer and have it replaced.

Over 10 years old I doubt Toyota will do anything about it. Where on the frame is this? I actually work in auto restoration (but we only do classics) and properly done frame work can cost quite a bit as it's very involved. I fluid film mine every fall and thankfully I don't have any real rust to speak of on mine. It was in the Boston area until 2018 when I bought it and brought it to NH.

An important component in speed of oxidation is temperature. Most people in northern climates that dump salt all over their roads in the winter, only do so in the winter, when temperatures are low and rust is slow. People who garage their cars will have far more rust in these climates than those that leave their vehicles outside. If you also have salt spray being applied the rest of the year when temps are higher, you get lots more corrosion.

When I lived in Florida, I would see 3-4 year old cars that lived within a few hundred yards of the ocean that were rusted out worse than 8 year old Michigan cars.

You could fix the hole in the photo without too much trouble, but when something is rusted like that in a spot you can see, there is plenty more that you can't. I bet hard to see areas like around the body mounts are mostly rotten, and places all over the body have started to rot as well, even if they are not yet visible.

Looks like driver's side frame rail, just in front of the lower control arm mount. I think that rubber hose with the stripe is the driver's side parking brake cable.

I finally had time this weekend to tap it with a hammer and wire brush the area.....NOT good. See below for more photos.

I know the 09's had this issue, could it be possible the very early 10's like mine that I bought in late 2009 have the same issue?!

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Heading to frame shop tomorrow then right into Toyota after to see what they have to say about this. I was just in there 5K miles ago for a massive fluid change service. They had the vehicle for a day and a half and NEVER said anything about this!

Back in my consumer car repair days, and living where they have a love affair with spraying and dumping as much salt as is humanly possible on the roads all winter long. I've seen every make and model rust out in a much shorter time than 12 years.

It's all about not taking enough time to keep the salt washed off. Most people don't, and a rusted vehicle is just the cost of living where we do.

It's well past any corrosion warranty, so I doubt Toyota will do anything. But good luck.

I do rinse mine well after snow/salt events, always have. I wash the vehicle frequently, wax it twice a year, condition the seats, etc. I could see if the vehicle was neglected but that is not the case.

I have a friend with a Tahoe the same vintage as mine, more milage and spends a lot of weekends in ski country and rarely, if ever, rinses under his Tahoe. I got under his the other day and it looks in great shape.

I was looking at a potential '23 4Runner as I kept waiting for the refresh but if Toyota will not take any ownership of this issue this will be my last. It's very sad because the only issue I ever had was a mirror switch go bad that was replaced under warranty. To me that is impressive, but I would rather have random small parts in a vehicle fail more often than the frame prematurely rust out.

Might be time for a Cherokee L.

Im surprised. We also get a ton of salt between Nov and April and my 08 isnt that bad. WIth the 4th gens- the earlier ones 03-05 were more of an issue than later ones. So my 03 rusted through after about 14-15 years, but my 08 still looks pretty good for now (other than the rear frame up under the bumper where a lot accumulates)

Yea something funky must have happened with that spot. got a chunk of salt inside it or the finishing process during production missed a spot for some reason

If the rest of the vehicle is in decent shape, and nothing available is on the market, you may want to fix it and suck up the cost.

Obviously whatever you were doing, wasn't sufficient.

Here's the '97 I bought new, and drove on salt encrusted roads every winter, and the Bonneville Salt Flats every summer. 22+ years old in this pic, the day I sold it. No rust, because I washed the undercarriage off whenever necessary.

A neighbor who bought a Mercury Mountaineer (Ford Explorer) about the same time that I bought the '97, had a rusted out hulk in 10 years, due to not washing the salt off frequently enough.

I lived 100 yards from the ocean for 8 years and drive salted roads all winter every year since 2010 and mine looks way better. Didn’t Toyota replace frames even on 10+ year old Tacoma’s? If mine had one spot that bad on the first new model year or one of the first 1000 off the line I’d be all over Toyota corporate, not just my dealer, pushing for a replacement or some sort of “consideration”. That’s a legal term, and because of their history with rusted out frames they may be willing to move mountains to make you “whole” whether with a new frame, repairing the frame or even offering you one heckuva deal to trade it on a new one… as opposed to risking the cost (both financial and the publicity) of another potential class action etc

While i appreciate toyotas reliability as much as the next person, youre not going to get very far with the dealership and corporate. Especially 10 -11 years out. Its impossible to a manufacture issue at this point and again and trying anything legal will take years and years with a david vs goliath chance

Our 03 was my wifes vehicle for like 7 years, and other than a little washing here and there it was effectively neglected. back in 2019 when we sold it the body was literally in perfect shape, so was the interior but the back of the frame (near where your issues are) were a mess, holes similar to yours. There is a class action law suit but only includes 05-09 vehicles if i remember correctly.

This being said, we sold ours to someone who was going to fix it but before doing so I found a shop over in Everett (T&T automotive) that was going to weld on some brackets (i would supply on the internet) they said it would likely be around a grand for them to sand it down, weld on the brackets and then paint it.

our 2014 was showing signs of surface rust when we discovered the 03's issues and i immediately coated the entire underside with rust neutralizer and then coated it with fluid film, so far so good but these frames LOVE getting eaten up... its pretty incredible.

Yes, frames made improperly by Dana Corp. Tacoma, Tundra, and Sequoia were the effected models, as they were made in America, and received those improperly made frames. Toyota won a 25 million dollar lawsuit against Dana Corp, and replaced a lot of defective frames, or bought back vehicles.

The 4Runner has always been made in Japan, and as a result, they didn't get those improperly made by Dana Corp frames.

But as I've mentioned, any make or model can and will rust/corrode eventually in a highly corrosive environment, if sufficiently neglected. Either intentionally or unintentionally.

The 4th Gen's have issues with this though and they are Japan built as well, enough so for their class action suit. The ones built in Japan might be a little better but are still horrible based on what I see. I have company trucks that are mid 2000's and neglected with NO issue with the frame.

Mine was not neglected as I have said. Washed frequently to the point where I have a quick disconnect hose set up outside my house to be able to rinse the entire 4R (top and bottom) after snow or salt events. It allows me to clip the hose on, rinse as needed, unclip and toss in the garage so it will not freeze and be useless.

Does the frame get rinsed daily, no, but enough where this should not be an issue after 10 years.

I took it to the shop this morning and they are going to repair it towards the end of the month. Sadly they also found more holes further towards the back as well.

Whatever vehicle I get next will be coated yearly underneath as you can't trust the build quality of anything it seems these days.

There's a class action suit because ONE guy in S. Carolina neglected his 4Runner, or didn't do his due diligence in inspecting it before buying it used, and now is looking for someone to blame, other than himself...

The 4Runner has never been more susceptible to rust than any other make or model of vehicle. Since they tend to be reliable mechanically, there's lots of older 4Runners out there. If they've been operated in a highly corrosive environment, and the owners efforts to keep rust at bay, (if they make an effort) haven't been verified as effective, then one day they might get a nasty surprise.

What I saw as a former Toyota master tech, was lots of neglect from owners. They'd buy a Toyota based on the reliability reputation, and then fail to adequately maintain their vehicle. Including adequately cleaning them in a highly corrosive environment.

Coating a vehicle yearly sounds like a good plan for anyone that assumes they are doing all they can for rust prevention, without verifying that their efforts are effective.