Deep growl n vibes. Rear diff??

Hi all. Ive got a deep growl/vibration that im suspecting to be the rear diff. How easy are they to chage

It really depends. My dad is fitting a KAM Drop In Locker to his Disco, which has a whining diff, so all that the KAM locker doesn't replace is being replaced is being replaced with parts from a spare axle we have. So far we've only pulled out the diff from the spare axle, which was about 3 hours work doing 2 axles (we were doing it in between other jobs so not 100% on time). It really isn't hard getting the diffhead with crownwheel etc. still on. I'm 15 and I was able to do the second one by by self (apart from the lifting!) So, when you say change, what are you changing? Do you have a complete assembly going in or something else? All I know (currently) is that it's pretty easy to take one out.