Eaton 18 spd oil at shifter knob

Are you sure its not oil in the air lines leaking out of the the exhaust of the shifter knob?

 

That was my first thought as well.

 

NO our point is, the knob itself never has any oil in it as designed. The only oil would be coming from way over excessive oil in your air lines from your air compressor. Like your compressor is smoked and blowing oil through your air dryer and filling your air tanks. Try taking off the supply line to your shift knob, it should be a push pull, and then put it in a bucket to see what comes out. What comes out when you drain the tanks?

 

Take the discharge line off the compressor and see if there is a lot of oil there.

 

Then just air down the system and pull the supply line to the shifter then put it in a bucket and blow that line out till it blows clean and put it all back together. You can also flush the shifter with some cleaning solvent to get the oil out of the shifter to stop the drips