Diff is bad, because it will crack under the wieght of the car and drop it\'s load of oil, then the next time you race a motorbike (like I do) you will hear a loud screeching noise followed by a bang and your back wheels might lock up ........ so not good!
Front of the car?
If you look directly behind the wheel at what is technically called "the lower arm" you will see something that resembles an "arm". If you follow this to it\'s "elbow" you will see what looks like a rubber bush (a rubbery toilet roll tube). This would be my first choice of jacking piont.
Don\'t forget, you aren\'t capable of jacking the entire front end, do one side at a time. And also, if you can\'t use wheel chocks, a brick will do just as well!
One handy tip is, when you remove a wheel, slide it underneath the raised car while you are working under there. A wheel refurb is easier to live with, than a CRUSHED HEAD!!!!!!!!!