Ok, I've been researching the LR4 ARB Rear Locker for years now. Every time I go down that rabbit hole it's a dead end. I haven't contacted ARB about this yet, but if someone wants to go down this rabbit hole by all means. ARB front lockers have been around for a while and are interchangeable with the LR3. The rear lockers were known to fit (a few) and was marketed to fit the LR4 for a brief moment (2013??) and was instantly pulled due to pumpkin size differences from the LR3. ALL of ARB literature and marketing had the LR4 removed. Lucky8 LLC, if you haven't heard of them, they specialize in Rovers and is a very reputable reseller of parts too. I just received confirmation that they will fit my 2011 LR4 HSE LUX 5.0L V8. They have this on their site https://lucky8llc.com/collections/lr4-lockers-1. I don't have the $$ right now, someone use their stimulus check and do this! I need to live vicariously through them! BTW... You're welcome!