I just got the word on my truck. It is NOT an AMU leaking. It is TWO AMU's leaking. One costs right at $100 and the other is $180. At least they have both in stock.
That is NOT in my plans. Their parts are just plain JUNK!! They KNOW there are problems with these AMU's. They refuse to fix the problem. I have spoken with people on this in the past. They just told me to live with it.
Their service is often not much better than their parts either.
I mean I just spent over a grand on air leaks just 2 weeks ago and NO ONE caught these!! I did ask them to check them all as well.
It is a kind of valve. They distribute air to different things. Like brakes, the lift axle etc. There are several on this truck. They are a nightmare. Hoses going in and out of them like worms mating. They are also poorly made.