Nissan Repair: Auto transmission, auto box, auto transmission

Question
Hey Von,

I recently replaced my S13 SR20 auto box, when I put to P & N ; there is hum inside the box what it can be….

Thanks


Answer
Stev,

If the transmission is making a humming noise in park and neutral it sounds like the high pressure bleed valve is sticking.  It should free up and if not change the fluid before thinking of taking the transmission down.  If the noise is really annoying you could remove the valve body and make sure the shift valve is free moving so the spring is not hanging causing the pressure bleed port to restrict.  Think of a wind instrument.  If the hole is restricted it will make noise.  If the hole is open and free no noise...