No dramas, the bearing in question is #17 on what JD call the reduction shaft, bearing part# ch11554. This bearing should in fact be the same as #2 bearing used on the input shaft #ch13508. Now the generic part number for the INCORRECT bearing is 6004 where the correct bearing is in fact 6204 for both the input and reduction shaft. JD type O.......? Not sure, but it’s a problem that has caused a heap of stress and $$$ with 550 owners and dealers alike. FYI the generic bearings are available at your local bearing supply for $10 AUD, opposed to $60 for a JD re packaged ones. Without yapping on too much I also have a sure fix for the transfer case failure if anyone is in need.