I pulled a trailer yesterday, about 13,000 lbs, and when I got to drop it off, I smelled what smelled like hydraulic oil. Are the manual trans on these trucks hydraulic and what would cause it to smell? I don't see any leaks anywhere. It ran fine @ 65mph for over 100 miles, fairly level interstate roads. Just curious. Only had the truck about a month. Thanks.

 

Over full diff will do that! and or tranny! Check the breather tubes.

 

the trany and transfer case use atf+4 and the diffs use gear oil so i would check them u could possibly have a leak somewhere I know the pinion seals are a common leak on these trucks.