Rep Power: 0

I have a 2004 honda civic 1.7L sohc that doesn't go into gear. When you turn it on it will pick up the gear you select just fine but after about 30 seconds to a minute it Will just slip . revs will go as if the transmission wqs in neutral. Its seems like somethingnis deactivating after the first couple of seconds of operation. We took out the transmissiin and swapped the torque converter. No luck with that and also changed the torque converter clutch solenoid. Just stumped. Please help!!!

 
Rep Power: 211

There's an internal filter ...if it gets clogged with debris it can cause shifting issue. Other than that could be valve bodies or clutch packs. Did you test and clean the shift solenoids and gasket screen?

 
Rep Power: 0

Yes we cleaned the solenoids and the screens and verified their operation. Is the filter internal requiring a transmission dissasemble? Or is it on the lower cover maybe?

 
Rep Power: 519

Yes.
And it usually means it's time for a rebuild, because whatever caused enough debris to clog the filter needs to be addressed.