Check your CV boot... if it is cracked, or not there, etc., then you have to replace the whole axle. You can further confirm this by looking inside of the boot... if it is cracked, etc... and if there is dirt/grime in there then your axle is ****ed, almost immediately. If your CV boot is just dry-rotted, but still in tact, then only the CV boot needs to be replaced as preventative maintenance. If you hear clicking then your whole axle needs to be replaced 99.99% of the time.