I have a '01 S10 P/U, FWD. This morning I went out to start it early as it was 7degrees. As soon as it started there was a rattle like a marble rolling around inside the pan or a pump cavitating. It seems to be coming from the tranny. I checked the fluid after driving about 6 miles and it was OK. It seems to shift OK. The noise went away after it warmed up but was back again after sitting for awhile. It has 125,000 miles on it.
Any ideas?

 

310sin24....I think it's those damn frogs again!!!! What's this world coming too?? lol

 

OK, I've got a little egg on my face over this one. What I assumed was a transmission problem turns out to be a bad catalytic converter rattling away. I've heard this before but I must have been having a senior moment and didn't connect the symptom with the associated part.