I searched and I found. I smelled the hot rubber smell recently after switching to magnaflow 12586 and doing my low beam HID- I actually thought it was the HID. I found my answer...that there is no answer.

Funny thing is.....my wife's new GX does it also, but it has a rubber busing on the exhaust next to the spare tire, that I suspect is the culprit.

Could be the combination of the new muffler coating and welding burning off

It's not coming from any coating on the muffler.
I have over 36000mi on mine and a few weeks ago will fueling up on a trip, I smelled it.
Haven't smelled it since.
Nothing rubbing anywhere....

Is it possible the drum brakes are sticking a little?

I doubt it. I've smelled it several times sice my T4R was purchased new....
always the right rear.

Funny you mentioned "always the right rear".

I have 212 miles on my 16', as I passed the rear of the truck, on the right/passenger side, I smelled that burning smell. I thought it may have been the brakes being that its new. I will bring it up to the dealer when it goes it for its first oil change. Gald I got fire coverage.

The 4th Gen has the same burning rubber smell as well. At 160k mi, I have no issues. Never did find out where the smell was coming from. I did hear/read some where that the drive line would spin out some grease and hit the muffler and cause the burning rubber smell.

Interestingly and probably unrelated but since I put the Sprint Booster on I have not smelled it.

Yea I also smell it with my 2016 T4R TRDP w/600miles. No idea what it is. Think its just the new car smell that burning off.

After 70k on mine, I still get the smell if I am driving it hard then park it in my garage. Its not a new car smell burning off.

Easy enough to reproduce on almost every 4 runner, before you get home, take your 4 runner on a long road and punch it from a stop to around 70mph. Don't let off the gas til you get there. Do this twice and then pull directly into your garage, close the door then smell at the right fenderwell.

I have two stop signs near my home, these are country roads with 4-way stops and nobody around most of the time. I've done this several times and tried the following:

turn off traction control, still has the smell
Slow down without using brakes hard, very light, downshift to slow, still has the smell

That rules out brake use for this smell. The only thing that I can tell is that it is definitely coming from the fenderwell area, which is also where the exhaust is. It is NOT coming from inside the exhaust, as the smell is not present at the tailpipe at all. It has to be the exhaust heating up and slightly burning one of the exhaust hanger rubber donuts near the exhaust.

Several folks have replaced their exhaust mufflers but still have the smell, so its not the actual muffler, and the only other thing that it could possibly be, aside from the isolator donuts, would be the heat shields, maybe they have some rubber undercoating, or use rubber grommets, or it has some sort of rubber sheet between it and the body? It is definitely a rubber smell, not a metallic heat smell.

One other thing I would check is the spare tire, only because its under there and its rubber. Maybe one day I'll drop the tire and do my little speed test to see if the smell goes away.

Of course, if anyone here has their spare tire off already, and can produce the smell easily, report back to see if that makes it disappear!

I have it.

I think it's coming from the driver side front fender area. Could be passenger side, but I've never ran over to check. It's definitely the front end for me though. When you guys are saying "the right side" is that passenger or driver?

Mine started around 4500 miles. Have about 5500 now and it's come and go.

Took it to the shop at the 5K mark and made mention of it. They looked around, said they couldn't see anything. Even let me get under too. As long as it's noted that I brought it in, I feel like I did my part.

Outside of that, I think it's just the character.

@mcarey86 right side meaning passenger side.

That's kinda what I thought.

Well, I guess I'm special. I believe mine is the driver side.

I have noticed this as well with my 2016 TEP, front driver side and smells like a hot/burning rubber...you are not alone lol maybe its the direction the wind is blowing haha