Powertrax No-Slip Traction Fits Ford 8.8" 31 Spline Axle 10 Ring Gear Bolt Rear Open Differential 7/8" Shaft 9206883108

This works exactly as advertised. It automatically locks your rear end which is priceless on an open diff 2WD truck for "specific applications" such as LIGHT off-road, slippery boat launches etc.This is not for you if you have a heavy gas foot - you have to drive "like a granny" in daily driving conditions or you can experience severe under-steer and in "city traffic" it randomly locks and unlocks as you go from gas to brakes, pull away from light and in stop and go traffic - this lock/unlock could get quite annoying for some very quickly.You can also "kick out the back end" at will, so really have to baby it unless going straight under slippery conditions (rain/snow/ice).There is a small learning curve after initial installation but at least if you absolutely hate it, it's an easy job to put the original spider/side gears back in.So if you "really want" an electronic or air locker and buy this "to save money" this will be a somewhat expensive lesson in spending the extra cash to get what you can live with because you will be pulling it back out.In city conditions and particularly in parking lots this unit "detracts" from handling and drivability.This is not some "cool add-on" just so you can smoke tires. If you have no real use for an "full time" automatically locked rear-end, this product is not for you. I live in a rural area with lot's of "open road" - in that circumstance I often can not tell it's there.While it's advertised as "more street friendly" then the Lock-Right version, that statement is true - but it is NOT "totally friendly, don't notice it's there" different, just a little quieter so you don't get the "slamming noise" when you turn a corner, but it still makes some funky noises that will cause others to look at your vehicle like there is something wrong with it.