Gerardo Connell,
    Sounds like the gear doors do not snug-up the the underside of the wing.  It is a very fine turning of the overcenter links/gear actuator, sequence valve, doors and gear down microswitch.  On jacks, do the main doors home-up solid then the sequence valve allows the inside small door to clamp tight.  I just am doing a 20 year annual on my older 235/320, readjusting all this takes a while.....  Good luck..and oh yeah do the tires track straight in toe-in and camber, maybe a wives tale, but a bit of tow-out is supposed to help track at speed on the Rwy..  this ought to raise 40 more posts.. Giggle   Don Skeele N320J