Burning Smell Coming From Rear

[NJshadow93]

Hey guys,

Just today I noticed a burning rubber/electric wire type smell coming from the rear. It was dark by the time I noticed it so I crawled under there with a flashlight and didn't notice anything unusual. I can smell it strongest from the wheel wells (whichever side the wind is blowing) or sometimes when standing right behind the truck. Any ideas? I did not notice any diff fluid leaking anywhere.

 

[Casper421]

Hey guys,

Just today I noticed a burning rubber/electric wire type smell coming from the rear. It was dark by the time I noticed it so I crawled under there with a flashlight and didn't notice anything unusual. I can smell it strongest from the wheel wells (whichever side the wind is blowing) or sometimes when standing right behind the truck. Any ideas? I did not notice any diff fluid leaking anywhere.

Anything melted on your muffler/exhaust? Like a plastic bag or something like that? :shrug:

 

[dtopgun515]

Hey guys,

Just today I noticed a burning rubber/electric wire type smell coming from the rear. It was dark by the time I noticed it so I crawled under there with a flashlight and didn't notice anything unusual. I can smell it strongest from the wheel wells (whichever side the wind is blowing) or sometimes when standing right behind the truck. Any ideas? I did not notice any diff fluid leaking anywhere.

I'm having same problem you figure anything out??

 

[NJshadow93]

No, it went away on its own about two days later. I'm thinking like Casper421 and something might have gotten stuck under there and eventually just burned away on its own. It must have been small though because I never saw anything unusual.

 

[Beertinted]

Lay off the hot sauce?
(Couldn't resist direct reply to thread subject line)

 

[TRD 4RNR]

Lay off the hot sauce?
(Couldn't resist direct reply to thread subject line)

I was beginning to think I was the only one

 

[Gecko123]

What did the burn smell smell like? Did it smell like plastic burning?

 

[NJshadow93]

Mine smelled like a cross between burning rubber and some kind of burning electrical wires.

I just thought of a possibility, I did some undercoating about a week or two prior, could the paint have burned away when the breather on the rear differential opened? Just a thought, not worried about the smell since it is completely gone. I used high temp (2000 degree Rustoleum) paint.

 

[superg3]

I have the same thing on my passenger side rear. Sometimes it's there, most times it isn't. Smells like burning rubber. I feel a bit of heat coming from near the rear shocks but can't pin point it.

 

[Gecko123]

I have the same thing on my passenger side rear. Sometimes it's there, most times it isn't. Smells like burning rubber. I feel a bit of heat coming from near the rear shocks but can't pin point it.

I know it's hot there because of he exhaust Could that be it.

 

[20034RunnerV84x2]

I had a weird smell when I was installing my cheapo seat covers this summer in 108* weather, but haven't noticed it since it cooled down. I figured it had to do with the heat so I wiped it off and continued. Check the underbody and if nothing is there it may be your imagination or exhaust.

 

[Wuzzy]

I have the same issue. I did just have new tires installed but I felt the backside of the tire and it was cool.

 

[marked]

I've noticed this a few times recently after going up a long uphill road, and after stopping there's a fairly strong burning rubber smell from the rear passenger wheel well. I see nothing wrong with the tire or shock, although I didn't get under the 4Runner to see if there was anything on the exhaust system - this seems to be the only condition where I get this odor after a prolonged uphill grade. Is this the catalytic converter smell that there was a TSB about?

Thanks for your help,

Ed

 

[jimmied]

I am having that same issue now and am going to start pulling things apart as soon as I have day soon. I am thinking maybe a stuck rear caliper but I am cannot find anything here about the rears failing...Any idea if the rears are in the same boat as the fronts? It is definitely my rear passenger wheel well.

Hoping someone found out the problem.

 

[zopperman]

Dragging parking brake?

 

[A10GAC]

If it's a stuck caliper you should be able to feel the heat from it on the wheel. I had one dragging last fall and was able to feel the difference in temp when I put my hand on the wheel by the lugs, one wheel was noticeably warmer than the other three. (On the wheel itself, not the center cap)

 

[3gsdad]

I had the same thing happening to me. It turned out to be the rear break calipers were intermittingly sticking. It took a while (and 2 trips to the dealer)to figure out. They did not stick all the time just randomly. I jacked up the rear end one day and the wheels spun freely so I thought the brakes were fine. It was not until one day it did it again and I splashed a little water on the rotors that I figured it out. The rotors were so hot the water boiled off of them. I had to replace the calipers and rotors.

 

[NJshadow93]

I am having that same issue now and am going to start pulling things apart as soon as I have day soon. I am thinking maybe a stuck rear caliper but I am cannot find anything here about the rears failing...Any idea if the rears are in the same boat as the fronts? It is definitely my rear passenger wheel well.

Hoping someone found out the problem.

The rears are floating calipers so they don't have too many issues with seizing pistons. What can happen and does happen is that the slide pins will seize from lack of lubrication and the floating effect will not be able to take place. This is an easy fix though, just pull the slide pins and grease them up with brake grease. It has the same effect as a frozen piston though since the caliper cannot move freely and uneven pad wear will occur. I'm sure it couldn't hurt to grease the pins if you're going to check everything out.

 

[MityMax96]

I know this is an old thread, so I can start a new one if needed
But wondering if anyone had an idea on this?
I am getting the smell from the driver side rear wheel.
Back in February I had taken the 4Runner to firestone, and they noted that on the passenger side, that a seal at the axle "had pushed out" or something like that and grease was leaking out.
And I think at the time, the smell was present on that side. But I can't remember.

So I am thinking that is what is happening on the driver side now....but I am not seeing any grease or anything around the brake hardware on the back side of the wheel.

Does anyone have any thoughts or insight on this issue?
Firestone mentioned that this was something they encounter often w/ 4th gen 4Runners.

 

[eleven14]

I know this is an old thread, so I can start a new one if needed
But wondering if anyone had an idea on this?
I am getting the smell from the driver side rear wheel.
Back in February I had taken the 4Runner to firestone, and they noted that on the passenger side, that a seal at the axle "had pushed out" or something like that and grease was leaking out.
And I think at the time, the smell was present on that side. But I can't remember.

So I am thinking that is what is happening on the driver side now....but I am not seeing any grease or anything around the brake hardware on the back side of the wheel.

Does anyone have any thoughts or insight on this issue?
Firestone mentioned that this was something they encounter often w/ 4th gen 4Runners.

Axle seals are pretty frequent failures but you should see evidence of grease being slung on the back side of that wheel. I'd get under there and see if you can pinpoint it

If it is the axle seal on that side, I'd also replace/relocate your diff breather. Both of my axle seals went over the course of 12 months and before replacing the second one, I replaced the breather on the rear diff which was functioning incorrectly (and relocated it behind the gas filler). My theory is pressure build-up from heat helped those seals fail but who knows.