My 2010 automatic has developed a strange whirring noise in 3rd gear , it does not do it for the first mile or two but it will then start whirring and it sounds like it’s from the rear , it is fine in first and second but 3rd starts whirring and soon as it goes into 4th it stops I can also make it start and stop whirring in 3rd by slightly taking my foot of the throttle and then back on , it will do it at any speed including up hill or down , I have had the diff and Haldex serviced last year and I also took the car to Bell engineering and Austin does not think it’s the diff or haldex , a garage had a quick check of the car and they only found a worn rear prop shaft bearing carrier, over the last 1k it’s not got any worse but it’s a little annoying