HP 4345 2nd Tray problem

Hi, I am not a IT tech guy by trade but it is my job right now to figure why we are having problems with HP laser Jet M4345 mfp, I have multiple 2nd tray problems. I will take it 1 problem at a time. 1st problem is I keep getting paper jam error message in 2nd tray when there is no paper jam. I have change the rollers and done basic cleaning. Took off back cover and tighten the spring on the paper pick -up assembly. Can that spring be to tight? Before when I had this problem I just made the spring tighter and the problem went away but I have adjusted this spring twice. I have also replace the paper pick-up assembly with a new one but I keep getting same error message. Any ideas what to do next?

Thank you
Ken

No paper anywhere, then it may be a pick-up issue. Change both rollers under the printer? The tray should have it's replaced too. Tightnening a screw in the delivery is not necessary. It's flag may be sticking, and will cause the jam.
A spring under the black plastic pickup roller shaft housing may have come off. Check for it's lift and return.
A sticky tray heigth flag may be stuck.
Check the solonoid flapper for the P/U assy.

Thanks, I am in my hooch right now but as soon as we get back to work I will try your ideas. I did change the rollers 3 of them. When you pull the tray out there are two on the right. Then on the right side there is a door at the bottom that has a roller also and I changed it. The spring I am talking about that I tightened .... if you take off the back cover there is a gear assembly.... someone told that is called the paper pick-up assembly, I am not sure whta it is called...but there is a very small spring on it. I was told that if I just tighten that a bit by making it shorter that the problem goes away but the spring is tight now and I changed the assembly. I am in Iraq, we have real bad dust storm here all the time, we are having one now my room is full of dirt in the air. These printers are always full of dirt you can not get them clean all the way. I will take your advice. I need to find something that tells what all the parts are.

Thanks
Ken

I have not been able to fix this yet, I am still having hard time getting back to working on this printer when I have so many others to take care of. Are you talking about looking for a spring on a flag that is located under the black plastic paper path that is in the same area where the ink cartrige goes. You need me to take that apart and look under there for a possible spring that has fallen off? Please excuse the fact I don't know the proper names of all of these parts as I am not really a printer guy, I work on laptops but having know one else I am now the go to guy oh boy nothing like on the job training.

Ken

I emailed the 4345 service manual.
It's rather large. I'm hoping that yahoo accepts it.
Otherwise I'll try something else.