I've had it with this 904, about to give up!

Air pressure test sounds fine to me. That being the case and you say you tried a different valve body also I'd take the converter to a converter shop and have it opened up and checked. You really should have done a hydraulic pressure test before you tore it down. That would have told you the hydraulic circuits are working ok. Now your just flying by the seat of your pants


Well, crap. Stupid me. The converter was rebuilt by a reputable converter shop (and stall upped at much as possible) so hopefully it's not that.

Will the air test reveal sealing issues with the pump/stator etc, or is it only good for the clutch packs themselves?