Rep Power: 0

I have a 2003 Civic (130k) with an automatic transmission that revs between second and third gear. The good news is that is it only does it the first time it goes from second to third gear after I start the engine. I have been driving on it like this for 50k miles. I didn't think it was a big deal because my 2002 did it too. I had a mechanic flush the trans fluid and put OEM fluid in at 100k. But this isn't really a problem if it only does it once right?

 
Rep Power: 284

Search this issue and you'll find all the information you need, it's been covered many times.

Sparks notes of the issue:
-01-05 civic as well as other Honda transmissions from the era are defective and prone to premature failure.
-Once the transmission begins to slip between 2-3 gear its on the way out, once it starts to slip when the transmission is warm you don't have much time left.
-Never flush a transmission, it does far more harm than good and often causes complete failure.
-Do an annual drain and fill with OEM fluid.
-Once it dies rebuild with a TCI performance kit, add an external cooler and external fluid filter for best results or have a manual swap done. Rebuilds never last as long as new transmissions.

 
Rep Power: 811

mine has been doing it for 50k miles also. it only happens when cold. in the winter it can happen alot til the fluid warms up. basically the trans in these cars is junk and over time the clutches wear out and the seals dry up. so until the fluid warms up everything, there is pressure loss when fluid slips past the internal seals and thats what causes the slipping. so long as the car drives normal when hot, i wouldnt worry for now.