If you're talking about the whole outside mirror assembly being loose, I've had the same problem. The securing bolts are on the inside of the door frame behind the black wing cover. It's the same cover that trims out the small in-door radio speaker, if you have one. If not, it's the cover at the lower forward corner of the window where it meets the door trim panel.

The small black triangle shaped cover just pops out when you pull it out and down from the top. The two 10mm bolts can then be tightened and the cover replaced. It's one of the most simple fixes I've experienced with my 4Runner.

I hope this helps.

Kip

mine did it too. even with a new driver mirror cause i ripped it off not paying attention (oops) it was a factory replacement toyota product, and even the new one rattled, seemed more then passenger and it was brand new.... maybe distance like stated on first page. i think you just gotta live with it

Kip's right, very easy to remove. On my '05 Limited the mirrors are help on by 3 10mm nuts. You have to pull the door panel out a bit to get a wrench in but all you have to pop is one fastener. Just give a small tug and the fastener pops right out.

I'm experimenting with 4" round mirrors in place of the huge stock mirrors. I find the stock too big and interfere with fprward visibility. Not a big deal on the pavement but they really suck on the rocks.

I have the same problem with my driver side. its just a problem with the glass/motor... if i press on the driver side glass there is a good amount of play with little effort.. on the passenger side i can press it pretty hard without it budging much... i moved the mirror in all directions to see if i can see if there could be something loose but there is a rubber boot from the back of the mirror to the motor so i assume its a problem with the motor or something within that boot. not sure i want to brave ripping it off yet... its used and i just got this car (ps, first post, hi )

since i just got this i was thinking about having the dealer take care of it, not so sure i can convince them to fix it though.

hey! mine does this too, but thats because of bumping the 12" in the back hope you find the problem, id look for screws on the bottom as well, or pivot the mirror, cause they often get hit by people in parking lots and such, making them seem loose.

Fixed my vibrating mirror on a '96 4Runner by tightening the three bolts that attach the mirror base to the door.

You'll find these bolts from the inside of the door under the triangular plastic cover in front of the window.
1 - Pry off the plastic cover by placing a flat bladed screwdriver under the leading edge of the plastic about mid-way down and prying the plastic straight away from the door.
2 - Three 10mm bolt heads will be exposed (mine were very loose).
3 - When replacing the plastic cover, insert the flat tab below the bottom bolt first, then press the ball-tipped stud into the round white plastic socket and press straight in to make it snap in place.

I hope this helps. The newer models might be different, and of course there could be something else that is loose on your mirror.

By the way, I have photos, but don't know what to do with the prompt for "URL" when I tried to attach them. Is there a separate URL where you first upload your photos?

I hate to necro post, but I recently bought a 05 4R and it has this same issue. My Google-fu says this post discusses this issue the most.

On our's, the housing vibrates independent of the mounting ear, that mounts to the door. I don't see any bolts or access panels below the housing.

I hoped with the number of these in the world, there would be a fix.

I have lived with this issue on my '05 Sport since I bought it brand new and have yet to find a fix for it

What about putting some padding in there so that there is more pressure against the housing mount points?

I figure I could make a wedge style shim and cram it in there, but I hoped to find a mechanical way to tighten down the housing before going that route.

I would be willing to bet that yours along with many others are the result of after market parts. I had a hawk fly into my passenger side mirror and broke it clean off (interestingly the hawk stumbled around a bit and flew off). I priced the OE part and found an after market one that looks exactly the same for 1/3rd the price. I put the first one on and thought I was going blind it shook so much. I sent it back and got another one. Same issue. I called the supplier and they said I could keep sending them back, but it wouldn't make a difference. You get what you pay for. So I have lived with it. If it was the driver side, it would be a different story.

Put a wedge so it can't vibrate.

I no longer have my '06 4Runner, but I'm pretty sure I ended up fixing this problem by tightening the screws underneath the mirror (they were either allen head or torx). I remember them being kind of a pain to tighten without scratching the door.

similar problem here as well.

the housing on the driver side can easily be wiggled with my hand.

tightening the bolts on the inside of the door wouldn't do anything because the base isn't moving.

From what I remember, these screws were on the outside of the mirror. Maybe they were under a plastic cap that had to be removed with a flat blade screwdriver? My mirror wiggled at the joint on the outside of the mirror and this fixed it.