I put a new Yukon Duragrip in my 8.2" ten bolt. Initial installation was quiet for probably the first 100 or so miles with Lucas synthetic gear oil with posi additive. Then the clutches started grinding on slow tight corners so I removed a bit of fluid and added a friction modifier from the parts store. This made no improvement so I pulled the cover and drained all the fluid. I replaced with GM gear oil and one bottle of GM friction modifier drove probably 20 miles or so and did figure 8's with no improvements. I then added one more bottle of GM friction modifier and repeated the driving and figure 8's with still no improvements. Does anybody have any suggestions or have I just not given it enough time/milage to work in yet. Noise is to the point it's embarrassing driving around town. Thanks for any input.