Which one of those 3 newer Lincolns is making a popping noise? They all seem too new to need balljoints.
But if it is a balljoint popping, WD-40 won't fix it. The ball is loose in the socket and will eventually separate from the socket. I'd have it looked at more closely if you don't know how to check a balljoint.
$270.00 & $720.00?? OUCH!! 2 hours labor & an over-priced $110.00 dealer parts dept. balljoint I'm guessing.
When I bought my Lincoln they tried to introduce me to the service dept. and I said, no need, I service my own vehicles. But just for kicks, we said hi anyway. That's when I noticed the sign at the door in big red letters that said...LABOR=$79.00 per hour.....I just laughed and walked away....after a cordial hello of course.:W
Balljoint from Autozone I'm guessing....$30.00 & free labor = $30.00 + $1.00 for hand cleaner.....that's a steal.:give