Hello and thank you for your question, My name is XXXXX XXXXX I will assist you today.The chatter you felling is caused by the posi-traction clutches slipping in the carrier. The type of noise you are describing is in most cases caused by a bad pinion bearing which will make more noise when under load and go quite when you let off the gas and it very likely once you get in there your going to find bad carrier bearing as well. You can usually stop the chatter by changing out the old fluid and adding new fluid along with some friction modifier such as Equa Tork. But its will not take care of the bearing noise your hearing. Unfortunately you are looking at a tear down and bearing replacement. This is a very common problem on the 2003 as well.If you have more questions and or need more help, please let me know and we can go from there.
Hi Ron, I typed a big reply and somehow got shut out of the system so I don't know if you got it. Well here it goes again. What is the carrier you are talking about...do the posi-trac clutches need replaced or just the carrier bearing? Is there a way we can test the pinion bearing to know for sure? If we do nothing and drive the vehicle will it ruin something or make something worse? Is it very expensive to have the rear end worked on or is it something we can do our-self? What fluid does the rear end take 90 weight? When we checked that it gushed out or shot out...could it have been too full? Thank you for all your help on this we really appreciate it.