Answer to 1st Problem -
This exactly sound like the problem I had - the problem originated when coolant was leaking from twp heating hoses and dripped onto my muffler - The pipes were OEM and had cracks (expanded) - replaced the pipes, no more smell - (These pipes weren't as major as the two up front hooking up to the radiator - small job
I cant remember the name of those pipes

(can't locate the receipt)
but they are located behind the air filter, driver's side, next to the engine
- You can try and check if those pipes are leaking - Hope that helps
2nd problem - I've recently rebuilt my transmission (after 277,000 miles - OEM - WOW

) - after the transmission wouldn't shift to 2nd gear sometimes