I have a 2001 duramax crew cab with 230K miles on her. I just replaced the CP3 becasue when I would tow our trailer, she would go into limp mode. She works great with the new CP3.

When I drive it without a trailer, the ride is fine. I"m not sure when the shocks were last replaced & I have owned the truck for almost 2 years. I towed our 1978 21 ft. Komfort trailer that weighs about 8K lbs to Eastern WA. When we hit pass, the roads were very bumpy and we could feel every bump as if I had very little suspension. I'm wondering if I need new shocks and/or if I need air bags. I can notice the rear does sag when I have the trailer hooked up to the truck. If I need shocks, do they make a good adjustible rear air shock for our trucks? Which brand of shocks? And what about air bags?

Thanks for the help everyone!

Ozz