I was driving home on the highway and all of a sudden my car got really loud! Especially when I started to accellerate. (even when at low mph when I was pulling into my driveway) could it be the muffler?

Noises are decieving. Cud be steering system or wheels or suspension. If ball joint fails car cud flip ovr.hav pro testdrive it. Seek a gudguy at surecritic.com

If it is not going into overdrive or lockup it could be the fluid or an electrical problem. Some of the shifting is controlled by solenoids now.
You may have to get a transmission shop to evaluate it for you.

run the fault codes
2 possible problems
1 low fuel pressure --pump or tank not venting properly
2--- failed cat converter blocking the exhaust at high rpm

for 15 minutes no problem but fix it the soon you can if not you can burn the o2 sensors

Possible catalytic converter is plugged causing exhaust to exit through a more frontal hole or spaces between exhaust components or gaskets between exhaust sections.

the right outer tierodending needs replaced.

your torque converter could have went. i feel its definetly your trans. i need more input

Exhaust leak?Bad water pump bearing,bad idler pulley bearing,power steering unit,

Since I work in government, my first question should be why would you need to go over 70 mph, but since I have a lead foot and a long list of speeding tickets on my record, I will keep my mouth shut on that topic. While cruising in the 70-80 mph, your transmission should already be in top gear, so you can probably eliminate the transmission. There are several possible causes of your problem including a vacuum leak, fouled plugs, bad spark plug wires, a dirty air filter, or a dirty fuel filter. Review your service records and see what has been replaced and when, then start looking at what hasn't been replaced. Sorry I can't be more precise without laying hands on it.

sounds as if you may be looking in the wrong spot. If different gearing is drastically changing the symptoms you may want to check the trans. or torque converter. sudden pop with engine rpm increase and lack of power sounds like possible band breakage in transmission or impellor breakage in torque converter.