Hello, Started to experience some gear whine about 300 mi after what I thought was a successful operation. I installed a set of FRPP 3.73 gears, Auburn ECTED 31-spline diff, Strange 31 spline axles, all new bearings/seals. Backlash upon completion was .0075 inches (I think this might be my problem). Ford recommends .008 to .015 I'd like to mention my pumpkin is solidly mounted to the chassis at all attachment points with spherical bearings (Heim Joints), so all noises usually dampened by the rubber bushings of the stock quadra-bind are greatly amplified. The upper arms have been converted to a single mount made by an extinct company called Evolution Motorsport. It was referred to back then as the Tri-link, the predecessor to the current Mustangs single upper control arm. Attached is also a couple pics of that, and google has many more. One of the things I was hoping someone of high experience could help with is the wear pattern in my pics. It seems to me that my pinion depth might be just one c**t hair too much. What I did do today is increase the backlash by .004, bringing the final reading to .0115 Bear in mind this is eleven thousands with another 5 ten-thousands (or half of a thousandth) tacked on, not 15 thousands. I am reading more often that this is the ideal (anywhere between .010 and .012). So with my backlash at eleven-point-five thousandth inches, I decided to take a break until tomorrow where I'll paint the teeth and run another pattern. I'd been working non-stop today on other junk as well and was pretty tired. The pics are of my original setup at .0075 in backlash. Tell me what you think/recommend aside from altering backlash which I did a few hours ago. Thanks!