We did insist, to the customer, that putting an oil drain valve on the auto transmission wasn't necessary as the change intervals were long and normally the pan is dropped completely when the auto transmission fluid is changed.
But Michael explained that his 2003 WRX is far from stock. We assume his Rex is driven hard, so naturally, it's better to be over-done with preventative maintenance, than to not.
Now with the EZ Oil Drain Valve on his auto transmission (he's got one on the engine as well), he is able to take samples to check the condition, easily flush the whole system and fine tune the filling. If he accidently over-fills, it's easy to remove some fluid.
For those interested in doing the same, the sizing for 2003 WRX auto transmission pan is 20mm x 1.5 which is our EZ-105 valve.
If you have any similar stories or problems, we'd love to hear from you. Contact Us.