I love my bird, but...

[Terrielynn]

I'm having a few problems, (125,000 mi V8)
The transmission slips sometimes going form 2nd to 3rd gears. Is this because I never take the overdrive off?
There is a weird (wooshing) rattle that goes away when the motor gets hot, sound like it's coming form under the car.
I worry everyday, because I think the transmission or motor is going to break.
I run premium gas to lessen the pre-engine ping I get going up hills, but still I get the pinging and it seems to lessen the power, Is this normal?
If I don't have an oil change about once a month, I loose power and it seems like it's hard for the car to go even 60 MPH?
This is a beautiful dark cherry red, camel interior, and I love it but sometimes I think I should trade it in.
How long do these cars last?
I've heard about the transmissions going bad.
The
Worrier