I have a 2001 Tundra access cab w/ 200000 miles. whenever i am coasting, I hear a terrible clucking growling noise coming from my rearend. I have been told by some it is my pinion gear. I something that can be repaired, or should i find a good used rearend and just replace? I have found some used ones between 450 and 900 dollars. Also how do I find out my trucks ratio?