4 low burning smell

while driving on the beach the truck doesn't really have enough power to properly shift from 1st to the MASSIVE ratio gap to 2nd gear on the manual without bogging down quite a bit. so i started using 4 low and to get to equivalent speed of about 60kmh i was in 5th gear. this was only for a few minutes but i started to smell a burning rubber smell. spent rest of day back in 4hi with no issues going same speed. tried 4lo again the next day and once again the burning rubber smell came back. crawled under truck and transfer case and diffs were cool to the touch and nothing seemed off. have no idea what cause the smell. any ideas?

done a google search and found quite a few posts with same issue but none ever got answered. some say grease coming off the u joints but hasnt been greased in a while and that should of affected 4hi too. and no it wasnt burning clutch.

atrac was turned off, rear diff locked (was in 4hi aswell), never noticed any abs light flashing or felt as if the brakes were being engaged.

 

Doesn't the sun visor 4x4 operation info card say to only use 4Lo up to 20mph or something?

I'm surprised you didn't hit the rev limiter non stop?

Either way, it's probably fine

 

Look at your cats, are any weeds or anything burnt from them? Check your oil housings filter etc you could be leaking oil and not know it

https://www.google.com/search?q=4+low+burning+smell+tacoma+world+site:www.tacomaworld.com&oq=&gs_lcrp=EgZjaHJvbWUqCQgAEEUYOxjCAzIJCAAQRRg7GMIDMgkIARBFGDsYwgMyCQgCEEUYOxjCAzIJCAMQRRg7GMIDMgkIBBBFGDsYwgMyCQgFEEUYOxjCAzIJCAYQRRg7GMIDMgkIBxBFGDsYwgPSAQkxMDE1ajBqMTWoAgiwAgE&sourceid=chrome&ie=UTF-8

 

nothing on sun visors in my truck. 5th gear in 4low is pretty much the exact same as 2nd gear in high. just much nicer getting there. i start out in 2nd gear. it may be 20 mph but idk what mechanically would give me that smell. originally thought i was getting transfer case hit somehow but it was nice and cool all over. pulled fill plug and oil was clean. back into 4hi and smell never comes back

 

none of those issues would be specific for being in 4 low. been googling a while already

 

Could just be the smell of front diff oil getting hot and the front cv seals getting hot.

It's probably fine

 

Are you aired down? Could the smell come from the tires? - your tires can build up temperature from internal friction (aired down) and also from external friction (the sand).
- But it seems that the first time it was only a short run...

I've used 5th while in 4lo - but only while very little/no power was required. In very soft / deep sand you may want to stay away from the overdrive gears. (5th & 6th)

I can't imagine what it would be otherwise...

 

all axles and diffs spin the same speed regardless of high or low range. they were cold to the touch.

 

fully aired up. same speeds were drove in 4low as they were in high. really the only mechanical parts that spin any differently are the trans output and transfercase reduction gears. so it kind of has me stumped unless the gears in trans are getting so hot so fast its sending the smell up through vent.

 

I do not believe it is related to the gears in the MT... I don't think they'd get that hot... (and Burning rubber smell?)

I'd look elsewhere...

I assume your clutch is not worn (and maybe slipping under power?). - you did say it was not the smell of clutch...

 

yea definitely not clutch. much less throttle even being used in 4low because of the close ratios between gears. in high im wide open throttle trying to get up into this engines insanely high torque curve. that particular sand saps so much power to accelerate.

this happened a few days ago and its been circling around my head tryna figure out what it could be since ahaha. il try and replicate again a 3rd time when i get back home in a couple weeks

 

It's 40mph, you can go higher, but only in short burst. The gearing let's you hit about 80+mph in 4LO. I haven't calculated it, but best guess for max speed in 2HI/4HI is 180mph, not that you would even get that high without some serious power plant modifications.

 

80 is probably about right. thats also how fast the truck can go in 2nd gear alone which is kinda bonkers (raised rev limiter with my tune)