In case your interested in installing a Powertrax Noslip, here's my experience. I installed it in a 09 F150 STX with 4.6 and open differential 3.55 gears. I needed additional traction in order to access the back of my property but didn't want to spring for a 4x4. The installation went well and by the book with the supplied instructions, anyone with a little mechanical know how can get it done correctly. I have 5000 miles on it and it has been fairly transparent on the road. I commute 90 miles a day to work and the only time it is a little annoying is when going from a dead stop then beginning a turn while going up a slight grade. Going uphill demands use of throttle and thus locks the axle then the turning results in tire squeal or breaking lose. No biggie, I expected that. Also, when on loose dirt and alot of throttle is used the rear can experience wheel hop. Again no biggie after installing traction bars on rear leaf springs. So, for the good stuff, the resulting increase in traction is awesome, I have yet to get stuck in places where I wouldn't dare go before. I can access my land even after a downpour, it's that good. As far as popping noise or ratcheting I have only heard it a handfull of times and was not bad at all. So for those interested in this modification I have not seen a reduction in gas mileage, there is no additional rear end noise while cruising and only an occasional pop or tire break loose when turning and install was relatively easy. Hope this helps anyone on the fence with this product, I was skeptical at first but now I am fairly confident of its durability and performance.