97 malibu won't go

the wife was driving the car. she said that the engine would rev with the gas pedal pushed but it wouldn't go forward. (no, it wasn't in neutral :biggrin: ) she had to reverse out of traffic, she said that it would barely do that. it wouldn't move forward at all. no dash lights/ CEL's or anything.

any ideas? we had the trans fluid and filter changed about 8 months ago, and we haven't noticed any leaks on the ground or anything.

it is driven about once a week, and the outside temp today was 0* f, but she let the car warm up like always.

btw-- 3.1 ltr v6, auto trans 150000 miles