Oil coming out of gear shifter

Air compressor is getting wore out and pushing oil into the system.

 

I can't answer that one ...sorry .

 

Get it done at a shop, you have to also replace the air dryer and flush the lines.

 

Drain your air tanks and see what comes out first.

What engine?

 

Also check your trailer air lines. Probably see some oil in them. Get it fixed ASAP or your going to have some serious problems down the road. Probably will need to change the air drier cartridge now and again when the cold weather starts.

 

That looks like transmission oil to me. That oil would be black if it was from the engine. The lines out of that valve go down to the range and splitter pistons in the transmission. Bet you've got one with a blown o-ring and its letting transmission oil bypass. Every time you shift the range or splitter it exhausts a little bit of oil out of the knob along with the air.