What year did Toyota switch to an open channel frame?

I am searching for a new Tacoma in Wisconsin and I have been checking out random trucks I observe in parking lots. The ones I see with open channel frames in the mid sections seem to be pretty rust free. I don't know how to tell the year so maybe someone here knows this. Even my 2001 which had the frame replaced in 2011 is mostly just surface rust on the rear section of the frame under the bed whereas the mid section with the enclosed boxed in frame is rotted out.

 

2005-2023 are all c-channel frame. 2024 onward is a fully boxed frame.

 

Thank you! It seems as though the open channel design holds up to corrosion better.

 

I didn’t realize the gen 4s are box frame. I assume there is some plan in place to mitigate rust? Is Toyota coating the inner frame with something?

 

I think I read somewhere that they have a wax coating on the inside of the frame from the factory. I guess time will tell how well that works.

 

Toyota just needs to go ask VW what they do on their cars. But the other thing is that stupid Top Gear segment on the Hilux made everyone think Tacomas are invincible and don't need to be cared for.

 

Yes, though the C-channel portion has two nested layers and rust can develop in the space between layers. Toyota added sealant to fill that space in 2018.

The cavity wax Toyota added in 2018 to the boxed portion is now applied to the full length of the frame. Drain holes are added as well; some drain holes are used by fabrication companies to mount sliders.