Mystery smell............

[TedW]

.....and no, I did not just consume the burrito blue-plate lunch special:

Yesterday we took a 150-mile drive around the Belgrade Lakes in central Maine. Lots of hills, some off-road, but mostly easy on-road stuff. 75 degrees and dry.
After dark we decided to take the interstate home - a 50-mile trip. After 20 minutes or so there was a strong smell like hot tar or hot/burning rubber. It was very noticeable coming out of the heater, but after turning it off we could still smell it.
We were doing +/- 60 mph with the hubs unlocked and the o/d in. My engine is new (3k mi). I did notice after getting home that my o/d and transfer case were fairly hot - normal, I assume? Next day I checked my fluids - all full. Nothing appeared to be burned, and all electricals were working fine.
Any ideas? I am assuming that the (relatively) high speed run had something to do with it, but I've done this before with no accompanying stench.
I await sage advice from the group.

[BackInA88]

I don't know?

My overdrive and t-case get pretty hot on highway trips.
Hot enough to melt the overdrive breather extention hose right off the fitting.
I switched to a nylon hose and will see how that holds up.

Had you greased you drive shaft resently?
Maybe it threw some excess grease somewhere that caused the smell.

[TedW]

I'll also recheck my o/d breather hose - the t-case breather hose was ok though.
Thanks - Ted

[KevinNY]

Mud baking on the exhaust has a nasty odor. The OD may be spewing some oil that is burning on the tailpipe as well.

[yorker]

Your transmission brake wasn't dragging was it?

[TedW]

..when I'm on the road.