Is there more then one place to replace AC refrigerant, 379 with sleeper

On newer PACCAR products, it should look like the pic, below. Also, under the hood, you should have a pre-filter and main filter behind the snap-on cover, on the right side of the firewall.

 

I've been in there looking for one in the past and didn't find one. had the wood top under the mattress out as well as the metal partition between the unit and luggage compartment. There is just a return duct at the end of the bed platform right side front corner. This is on a 1997 379.

 

the filter is somewhere between the return vent and the ac condenser... every truck I've had the filter is right in front of the ac condenser with a 1"× 8" panel that pups out or 2 screws to remove so you can change it...

How long have you had the truck...??

 

The reason I asked how long you've had the truck is because if someone took out the filter and you ran the ac or heat without a filter your going to have bigger problems

 

I bought it Dec. 03. I'll have to go back in there and check. I've never had any problems with the a/c, front or rear.

 

I buy a house filter and cut it to size. Much cheaper that way. One big filter makes a lot of smaller ones.