Burnt plastic smell from under vehicle

My 2013 trd offroad has developed a burnt plastic smell you notice when you get out of the vehicle like its comming from underneath, a month ago i did run over a piece of plastic that went under the truck on the interstate then it came out. Just now noticing the smell so i dont think its tied into that incident, i crawled under the truck and checked ever inch of the exhaust system and its clean from front to back, smells strongest from rear door back and can smell it on both sides of the rear wheel wells of the truck but can not pin point it, doesnt seem to be leaking nothing that i can see from underneath, it dont take much driving to get the odor, i recently logged a 2 way trip on the interstate for 10 hours and didnt notice anything, seems the worst on short runs around town.

 

How many miles on the truck?

 

70,000

 

I get this quite often too, I hate not knowing what it is. I like to think its a bit of grease flinging off the u joints and hitting the exhaust, but probably not.

 

Ever change the rear diff fluid?

 

I have not changed the fluids i just gotthe truck about a year ago, would the rear diff fluid cause a smell outside of the casing, the truck runs and drives smooth as silk with know weird noises.

 

Had a plastic bag get wedged up between the muffler and body of my gf's 4runner, possible one got jammed up there?

 

Thats interesting, the dealer changed the oil on it about 3 weeks ago ill look for grease, but i had a 1st gen that got greased and had a smell but it had access grease slung all under it, but i havent noticed any thing out of place underneath this one

 

It’s probably not the problem but I would change out the rear diff oil

 

I looked on top ofthe muffler since i ran over the plastic it was clean, this sheet of plastic that went uder the truck was likeca 4' by 4' large piece but it blew on through,

 

Im in the process of getting all the maintenance items taking care of

 

Cool. Good luck with it!

 

I would be surprised if grease is slinging out with temps in the 12 degree to 25 degree range, grease ought to be cold and hard lol

 

Took a short trip across town and when i got back noticed the smell so i immediately popped the hood and could smell it on the driver side, looked around with a flashligt and didnt notice any apparent leaks, only thing ive had done was an oil change about a month ago at the dealer, hopefullyitwill getabove freezingtommorrow and i can crawl up under it again, im going to check thevoil drain bolt which im assuming isnt covered by a skid plate.

 

Lubricant/grease/oil does not smell like burnt plastic. At all.

At least not to my calibrated nose.

When you get to examine things, be sure to look all around the cats. They get much hotter than the exhaust or muffler.

In another marquee I owned, a specific point on the motor was notorious for leaking oil that would run down on the cat. Smelled a lot like burnt clutch, and was in the right area. Since I was racing a lot, folks kept telling me I was toasting my clutch. I assured them not to fret, as my times kept getting better and my position on the leader board was passing them.

 

I have had a plastic smell on my 2013 also from time to time. It smelled like a Wal*Mart sack stuck to the exhaust. To date I have not found anything.

 

That is crazy, im halting all future mods and progress till i find out what the hell is going on, ive had the truck a year now and this just started, i mean geeze just a 10 minute trip gets it smelling, i park it in the same spot and there is no sign of anything leaking thats making it to the ground.

 

Do you have a manual transmission?

 

No mine is automatic

 

Stuck caliper? Had this happen. Thought it smelled like melting plastic too