Acert cat problems

Runs fine when not under a load?

Any codes/check engine light?

 

The tapping noise makes me think that something has come loose, possibly from when the overhead was done.

 

I wonder if a dead injector would cause that, I know they'll make it shake.

 

Take it to a Cat shop or buy the tools and do it yourself. It sounds like you need to do it ASAP before you grenade your motor. I found there are very few truck dealer mechanics that have a good understanding how to do an overhead on an Acert Cat.

Kenworth of Dothan, AL did an overhead on mine... never again. They missed two broken rocker studs on 5 and 6 and royally screwed up the adjustment. The jake was popping back and had no holding power and it rattled and ran like crap.

I got it back home, pulled the valve covers and VVA housings, and found the broken studs which they should have seen if they actually did the adjustment right.

Long story short, I bought all the tools to do it myself, replaced all the rocker studs and it ran like a champ.

 

Tapping noise under a load on an Acert is likely a broken rocker stud.