Don't forget to change your air dryer annually!

Learned that hard way: 3 days ago on my way to Los angels purge valve stuck open because it was completely clogged.
Midnight, nobody’s available till morning time, I’m on a shoulder…
Called to my father and he explained how to bypass air dryer temporarily (I’m glad I got tools) and made it home.
Took it apart, cleaned everything and changed purge valve and filter. Now will change it every 6mo/50 k miles

 

That is very bad. I would change it today. You don't need any tools except a filter wrench. 2 minute job with a filter wrench.

If your truck is new enough to be an automatic you're quite lucky you haven't totaled your tranny. Many trucks, Volvos for sure, have reliable auto trannys if you keep a good air dryer filter on them. If not and moi$ture get$ in the $y$tem, well, you know what I'm saying.

 

Here is what mine looked like. I put a very small amount of grease on the threads since the old one appeared to have grease applied. It was like $25 from my Kenworth dealer. Old one came off easy with the filter wrench I bought.