Ok might be parting out my 4runner frame rotted by gas tank
Has 178k on it motor has 110k put it in with 82k on it did water pump timing belt crank seals hydraulic tensioner thermostat and valve gaskets in it at that time. Valve covers leak a little no other leaks on the motor. Tranny is good shifts fine no issues along with the 4wd system. Leather interior seats are in ok shape no major tears hatch is rusty but doors and fenders no rust that I can see. Has the big flares and running boards.

 

It's my dd and I'm still driving it BTW.

 

Before you part out your truck take it to the dealership. I found frame rot in the exact same place you mentioned. This is a known problem covered by Toyota. If you bring it in and they can see the rust damage, they will do one of two things, pay you for the truck anywhere up to 10,000, or completely replace the frame. I was lucky to have my entire frame replaced, doubling my truck's value. You may even want to call Toyota service before you bring it in to confirm what I am telling you. There was apparently a bad batch of steel in an American steel company manufacturing the frames.
Here is the only caviat, you have to have participated in the frame program a couple years back when there was a notice sent out to owners that the frames had to be inspected. At that time the frame was either replaced, or a corrosion resistant spray was applied. Mine got the spray, which I think made the rust problem worse. This extended frame warranty for I believe up to 14 years. Anyway, good luck, I hope this program applies to you.

 

Thought this only applied to the Tacoma. But I will call and find out