Towed a 8000# horse trailer 4K miles (MD to WY and back), I had a slight wiff of 90 weight oil when I'd stop for breaks a few times on the way out.
I came home a different route that brought me through the Cumberland gap on 68. When I stopped for fuel The smell of 90 weight was throughout the truck. no drips from the diffs at all.
Should this be a concern??


Thanks,
Slack

 

Check your axle seals, if not leaking the smell may be from oil vapor just venting. Check your axle vents make sure theyre free to vent. If your seal/s are leaking and it contaminated the brake lining youll need to replace the lining when you replace the seal.

 

I should have stated it was a 2008 F350 dually.
Guess I need to put it on a rack and pull the tires.


Slack

 

If you can't find an leaks they probably just got hot.

That is the one concern to keep in mind with modern big power Diesel engines. They have enough power to climb any grade at speed if they are loaded within factory spec but that generates a lot of heat in the diff.

Class 8 OTR trucks (some) have diff temp sensors, on a warm day on a good grade if you don't drop a few gears with a big motor you can easily cross 300+*F diff temp. You could easily crest the hill at 55, or 65MPH but your diff is going to suffer.

I usually just jump in the slow lane when pulling a long grade with anything over 5000lbs, that gives me the best chance of keeping things cool.

 

I would say to check the vent tubes and seals. I had an 08 and I towed that route many times and never had an issue.

 

Here are the gauges from my Kenworth, for illustration purposes. I had a 97 f250 that had the axle seal go out. You couldn't see the leak, but it slung oil all over the inside of the drum and I had the same smell every time I stopped.

 

Thanks for the info guys,
it's a V10, trailer was only 8000# but I was pulling at 75mph flat and 55-60mph up grades.
I am going to put it on jack stands and pull the rear tires and diff cover and check things out. I'll change fluid and possibly a large capacity diff cover.


Slack

 

Had that same smell once with my F150 4x4....

Was the front differential and it was smoking hot!
I had just towed about 250 miles and found at my son (was little back then) had been playing with the hub lock on the right front and he had locked it.. The Left front was free wheeling....
Luckily there was no lasting damage but I changed the fluid in the diff... It was pretty rotten smelling! Not that Hypoid ever smells good....

 

Big-Foot,
that's the 1st thing I checked they were unlocked.


Slack