Ac blowing at 55 degrees....

Reciever /dryer should be replaced every time the system is opened up or when Freon has leaked out. Replacing them everytime the system is worked on is cheap insurance that the system will cool properly.

 

I keep a thermometer in my center vent...All the trucks I have had with good AC were around 40 degrees.
The truck I'm in now pulls down to 35-38 on recirculate and it was 95 outside today.

55 is a bit warm.....I love the sleeper very cold at night!

 

Air cabin filter, (I believe it's called that). Mine was dirty and works ok after changing.

 

KW doesn't really have much of a cabin air filter. Just something that looks like 3M scotchbrite that passes for a filter. I didn't get my truck back yesterday but will today.

 

The T600s/T660s/T800s/W900s et. al do, but not all models. T700 has a disposable filter which is installed in front of the windshield on the passenger side. T680 (and I believe the T880, as well) use two disposable filters - one thin and one thick one - which are particularly prone to getting clogged up. Plus, several models also have an additional mesh filter in the MVAC compartment which is generally expected to not require maintenance/replacement, but often does.

 

Another thing to check would be the condition of the condenser fins. If the fins are bent or full of debris that will reduce air flow through the condenser and will reduce the amount of heat transfer that takes place which will raise the vent temp.