As most of you know I had to replace the rear drive on my 2005 LT with 41,281 miles. I had caught it before it had shown any problem by having the oil analysis. I had been using Mobil 1 75W/120 Synthetic gear oil changing it about every 3,000 miles. After replacing the rear drive I was using BMW synthetic 75W/120. I changed it at 600 miles and again at 2,000 miles. Both times it looked pretty dark but no metal on the drain plug. I then took a 2,700 mile trip and when I got home I drained it and sent it in to be analysis. Again it was pretty dark. I got the test back and it said iron elevated other readings appear to be normal. Resample in 2,000 miles to monitor. This was the wear metals. The oil condition/particle count was all 0, which is good. They told me there was more wear than they felt normal, which shows oil is not doing a good job. They suggested Red Line heavy shockproof gear oil. I see where there are several on the website that are using this. I had a hard time finding it in the Omaha area but finely did. I had about 1,000 miles on the oil in the rear drive today when I drained it. This was the BMW 75W/120 oil and it came out just like new oil this time. Nothing on the drain plug so I feel the rear drive is cleaned out. I filled it with the Red Line heavy gear oil. It is just like heavy red paint. Since I had it I also changed the transmission using the Red Line oil. I will run it for at least 2,000 miles then send it in and have it analysis. I would like to hear comments from people on here that are using the Red Line oil. When I get it analysis I will post the results. I feel having the rear drive oil analysis is the best way to caught it before breaking down on the road.