I have a 2003 Bonneville SSEi. It has 39000 miles on it and the transmission has already been slipping on me, but only every once in a while. it has slipped 5 times going from 1st to 2nd in the last 3 weeks. It is not throwing any codes and there are no metal shaving in the pan or the filter. Any ideas of what is going on? I really appreciate any help anyone can give me!

Check your tranny fluid level first. It'* simple to do and may very well be the problem.

Could also be some other problem with fluid, such as bad filter and dirty oil.

EDIT: Forgot to say to check your oil level in the first sentance.

I had it into the dealership and they checked the fluid and even changed it. They took the pan off and there were no metal shards in the pan or in the filter and the valve body looked normal.

So what was the dealer'* diagnosis?

The dealership diagnosis is they don't know. They can't get it to throw a code and it will not do it while they are driving it. They have driven it 30+ miles and still know nothing. They don't think it is anything mechanical since it is intermittent and are thinking it is an electrical component. Bottom line they won't do anything till they know for sure.

Under warranty?

If so.. tell them to keep it and give you a rental until they fix it.