Burnt smell
 

Hello Hummer Enthusiasts!

Looking for some advice on my '06 H3. During a 4 hour haul of a boat, I noted that the 4H Lock had been engaged (believe it was the dog that hit it). We were on the HWY doing about 60 MPH when I noted the 'Service 4WD' message. I estimate we had been driving with 4WD Lock for about 5-10 miles. I slowed down but was unable to disengage the 4WD lock until I pulled over to a complete stop and turned off/restarted the engine. I was able to complete the trip with no major issues. The 'Service 4WD' message has not returned.

The problem is that since that issue, I have noticed a burnt oil smell although it is not motor oil. I suspect the transfer case overheated but wanted to throw it out to the forum for confirmation and additional thoughts. If it is the transfer case, is it a simple procedure to replace the oil?

Any thoughts would be appreciated.

Thanks,
LifeIsGood

my guess would be that your correct about the transfer case...but i'm not an expert. heres a video on changing the transfer case fluid....

i could almost hear the audio. wonder why sometimes I play a video and it hurts my ears,others I cant hear?

yeah the audio is quiet....i just cranked up the speakers i have plugged in. hope this video helps.

Thanks for the video - that should help once I put it up to look at it. If it is the transfer case, are there different types/grades of transfer case oil? Recommendations would be appreciated.

Still looking for confirmation from others that the problem I described is likely the transfer case or other theories.

Thanks,
LifeIsGood

should take the same fluid as your transmission for the 06, but check the owner's manual

OK, after a little investigation, I believe the smell is coming from the front differential. I removed the skid plates and noted a small amount of fluid around the drain plug (very small as there were no drips on the back of the skid plate). The fluid smelled exactly like what I have been noting since driving on the highway in 4WD lock.

So the remaining questions are:

• does highway driving in 4wd lock put stress on the front differential that would cause the leakage and smell?
• is it possible that the differential oil overheated and should be replaced?

Thanks,
LifeIsGood

I posted info on lock mode damage. everything in the drivetrain is stressed when you drive in lock mode.
when you turn,any amount,all 4 wheels move at different speeds. they bind up in lock mode. something gotta give,it gets hot from binding metal to metal when the tires cant slip on dry pavement.

its an ongoing never ending topic here despite guys posting how to make warning lights,like the factory shuda!
oh,should the fried,cooked juice be replaced,well yeah.

hello, i have an 06 as well. i dunno what the video shows but the 06 needs to be filled to the drain plug then another cup of oil goes in through the speed sensor hole for t-case. dunno about diffs. gl

if you are worried just drain and replace. I run full synthetic oil in mine


If you are smelling it, it needs replaced anyways. whether the leak was caused by driving in 4hi lock, I could not tell you, but I would just pull the cover check everything reseal it, and replace fluid with new.