Auto Transmission Question

[MistrMackey]

Ok so I don't know much about auto transmissions, so bare with me. When I'm driving down the road at like 15 mph in drive with o/d off and I punch it the tranny kicks down a gear but it doesn't seem to pull, I've noticed this time and time again at different speeds and rpms. I start my car this morning ( cold start) my belts squeal (need to be tightened or replaced) and when they stop I start driving , same as before about 10mph 15mph I punch it and BAM thrown back in the seat , it feel like it kicked down into 1st and every other time it just kicks down to 2nd ? I don't understand it why can I only get my car to throw me back in the seat when it's cold? does it have something to do with my belts? or my transmission? or what? please help I need to get to the bottom of this , if I can't I'm gonna scrap the auto

 

[Talyn]

I doubt there is anything wrong with your car, other than squealing belts, if you punch it in the 10-15 range it will downshift to 1st, it will most likely be in 2nd gear already, or possibly still in 1st, but it will not be in 3rd at those speeds(I'm assuming the autos are 4 spds?), so if it makes a downshift, it is downshifting to 1st.
As to the power issue, when it is cold there is no heat soak, which means the engine is ingesting cold air, cold air is dense air, and dense air, is more oxygen per given volume, aka. more power. A good example of this is a season in which it is hot during the day, but cold in the morning, punch it when you go to work in the morning, and when you leave later that day, you will notice a difference.