Toyota Tacoma Noise Mystery - Help!

Ok…I really need some help. I have a 2002, Toyota Tacoma, extended cab, V6, 4WD. I purchased this new back in CA, before moving to CO. When the weather turns cold, a noise begins to start. The noise appears primarily when I am decelerating (just taking my foot off the gas). The noise sounds like chains rattling. I would equate the noise to the sound a diesel pickup makes (low rumble). The noise sounds (to me) like its coming from behind the passenger’s seat in the floor. The noise is quite loud (people walking on the street can hear it and its apparent something is not right with the truck). The only constant thing is that it must be cold out. So, when spring comes, I tend to forget about the issue. We are having snow this weekend in Denver and its starting again. I have taken this to multiple mechanics over the years. They tighten everything up, but cannot seem to find or fix the problem. Just an FYI, I am not a mechanically inclined person and I don’t do work on my own vehicle. Any thoughts and help would be appreciated. Thanks so much.

I am assuming you get the noise when you are in 2WD High. I am wondering if your problem might be noise from the transfer case as the front axle drags the idle front drive system along when greese is thick and cold.

To diagnose the problem you might have your mechanic temporarily remove the front drive shaft and see if the sound changes or abates.

Let us know any further details.

What about a rattling heat shield over the cat?

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