My husband and I raised 3 children and certainly the teen years are difficult. They're bridging into adulthood but now more than ever, they need discipline and love and affection. You weren't very specific as to what his "unruly behavior" is but in regards to yelling at you and being mouthy that's simply an issue of respect, if your children don't respect you now, they never will (I have a friend whose now 27 year old son is proof of that). If this behavior is something new, you may need to check for any drug or alcohol usage and don't let him try to tell you his room is off limits to you. You have to understand also that their discipline MIGHT inconvenience YOU and be prepared to deal with it. Like taking away the car keys.
Since I don't know the specifics about YOUR child, I can only tell you what we did. Ours are now grown up and all 3 say they now appreciate the discipline they had growing up.
1) EVERY Sunday we went to church and the kids went to youth group - it wasn't optional. They also had service hours to perform for their church and their school without which they couldn't graduate.
2) We sat down at the table EVERY day for supper and talked to each other - if they had activities, I scheduled suppertime accordingly, sometimes we ate at 4:30. And every morning I cooked breakfast for them. If you cook it, they WILL eat it and eventually their friends will begin to envy that and it becomes a source of pride for the kids. It's also another opportunity to talk to them.
3) They had a curfew of midnight PERIOD.
4) They each had specific chores other than keeping their room clean. EVERYONE contributed to the household in some way. If these things weren't done, they lost privileges.
5) Our teenagers understood that our home was NOT a democracy! NOTHING was off limits to their parents.
6) Every time they went out, we were in touch with our kids' friends. If they said they were going to so-and-so's house, I talked to so-and-so's mom or dad. I would also require them to call me from their HOUSE PHONE. Cell phones give these kids WAY too much latitude.
7) Most importantly, I hugged my kids EVERY day and told them I loved them and that I needed THEM too, that they were important to me and always knew it. I reminded them constantly that if I didn't CARE about them I wouldn't care where they went or WHAT they did.
8) We didn't just give them money any time they asked. If they wanted money for entertainment, they had to get a job. Kids who are busy don't have time to get into trouble and they develop a sense of responsibility.
9) We all shared ONE computer so the time on it was carefully scheduled and monitored. In an age where everyone has their own laptop, that falls under the "not a democracy" rule, parents MUST have access to their childrens' computers. If you're not very computer literate, TAKE A CLASS!! It's important to be at least as smart as your kids where computers are concerned, the internet is another place they can go for which they don't need car keys and can be just as dangerous.
What I have discovered as the MOST difficult part of parenting is NOT the two's, and it is NOT the teens, it's the change I have had to endure when I have had to learn how to let go and realize my job is done. It's a little akin to teaching them to ride a bicycle - pretty soon you have to let go of the seat and let them ride alone. Are they going to fall, absolutely - didn't you?
A note about me: I am married, my husband is an airline pilot and was often away from home. My children are now 27 (boy, college graduate, engineer) married almost 3 years (no children yet), 25 (girl, college graduate, kindergarten teacher) and still looking, also still living at home, 23 (boy, college graduate, pilot flying night cargo soon headed to the airlines) will likely soon to be engaged when his girlfriend graduates from college. All 3 of them now thank us for being strict with them, they say it made them better people.
I hope some of this helps. WOW.... sorry this got SO long!!!
S. M.