It's my 05 1500HD. I have zero issues in 2wd and it's not the belt on the engine. Tonight after running 5 miles or so in 4 hi when I stopped I got the distinct smell of something rubber getting hot ( no not electrical hot, like you are burning a tire). It's from the front and probably moreso drivers side wheel well. The truck makes no noises in 4 hi and I recently had the t-case encoder motor replaced. I rarely use 4X4 for any extended period of time so possibly this is why it goes un-noticed. It's not my tires either.

I am wondering if it's a U joint getting tight and hot, thus getting the plastic hot that holds the caps in. Thoughts?

 

Drove it again. Ran 4 hi for a few miles and the smell is back under the truck. I can't source it, just a smell of burnt rubber. The U joints on the front driveshaft are cold to the touch so it's not that. Maybe it is the belt and it's simply co-incidental it did it after using 4 hi for a while. Or a pulley is seizing up, yet it's quiet about it, lol. My truck runs a lot being it's my work truck and this is the first time I have had any issues. I will drive it again in the morning leaving it in 2wd the entire time and see if it returns.

 

If its the belt you will a lot of dust on the front accessories

 

Everything under the hood is clean, although really if it's the A/C compressor belt you wouldn't see it. The truck ran a good few hours today and this only happened after using 4wd on the way home, and has never done it previously. It's odd, but tomorrow may tell more.

 

Is the driver's wheel very hot when you smell this smell?

 

No it's not my tires. Driving on frozen roads on snow and ice the tires are dead cold, trust me I thought it could be something dumb like that too.

Here is an oddity that I might mention for fun if nothing else. I had a shop put in the encoder motor and then proceeded to drive about 200 miles that day afterwards. Something felt funny with the front end after a while and it ended up being somehow my front diff was locked. The T case was in 2wd but it hopped turning. Shifted from 2 to 4 and back to 2 and it disengaged. Sticky or faulty actuator....... maybe. Odd it only gave trouble after the truck was worked on. In fact any oddities with the truck and the 4wd have been since I had the encoder motor changed. I am calling them Monday and they can deal with it!

That is after it has to last for 2 more days at work and then drive 225 miles home.

 

If you have a matching set of all 4 tires(exact match), then crawl under there & smell the fluid in the t-case, and smell the fluid in the front diff. Maybe you will find some burnt fluid in one of the gearboxes.

It's possible that your front diff is going out.

 

Tires are a matching set of 4. I can probably take a quick peek at both the front diff fluid and the t-case. I changed both maybe 15000 miles ago so it would be obvious if either were an issue. The original fluid in the t case was black ( but not burnt) and not blue like it should have been, but I don't find that out of the ordinary for a 246. The front diff was grey, but again not out of the ordinary for a diff that had never been changed prior. The truck had 55K miles on then and 70K now.

 

After I wrote the last post I started the truck, it probably idled for 20 minutes ( it's cold here and I can't stand that inside a vehicle plus the fuel is paid for, lol) and then drove the 8 miles or so from the camp to the plant. When I got there it's of course windy and miserable so outside I really couldn't smell anything out of the ordinary. I pulled the truck into the shop here and there is no odor whatsoever.

So since this trip was done entirely in 2wd that leads me to believe it is 4X4 related for sure and not a belt or whatever. I will whip the truck into the shop later and check my diff and t case fluid and report back what I find. I know they are both not leaking at least as the one nice thing with this truck is it stays bone dry underneath.

 

Just checked everything visually under the truck, and nothing. The transfer case still has nice blue fluid in it and the front diff oil is nice and golden, neither smell burnt. The actuator on the front diff had some old grease on it probably from the idler arm. I mean only on the actual plastic where the electrical connector is closest to the idler. It's not leaking anything as it's definetely the grease I use on the front end slopped onto it lol. The only leaks I have are oil cooler lines ( what a surprise) but that's nothing a couple hose clamps can't fix. Key on engine off and I cycled it a couple times. Everything works normally and shifted fine. There are no vibrations or pulling when driving either in 2wd or 4X4. I am kind of at a loss. Both belts are old ( the main one is a original off a 40K mile 05 Escalade I had when I swapped on my AD244 and it might have 50K miles on it now, no cracks looks new still) and the A/C looks original. Nothing seems to be touching the exhaust anywhere either. CV's look good, boots aren't torn.......

I guess I will dive into it moreso at home and see what happens today and tomorrow.