transmission problems?

i had a flat today when i went out to go to work. i put my spare on and it was alright at first but then about halfway to work my car started acting funny. it wanted to pull really bad and sqeeling and i didnt have much power by the time i made it to work it wanted to stop when i would push the gas it would go and then die off not the engine dying off but it seemed as if it was in neutral and then kiking into drive. There was some smoke that smell sort of like natrual gas. im thinking it has something to do with my transmission because when i just start it up and run it without moving it sounds fine. I was thinking that it might have something to do with the smarttrac all wheel drive and maybe it is trying to transfer the power to the front but it cant because of the smaller spare.

The spare should be the same height as the rest of the tires or you will burn up the transfer case.

The spare should be the same height as the rest of the tires or you will burn up the transfer case.

so if you have a flat on the front and only have a "doughnut" spare would you be better off putting the doughnut on the rear and putting a full sized tire on the front?