There are a few things you need to remember when using a T3 or an eVod or a ProTank:
1) Make sure that the atomizer coil is screwed into the base tightly--they often come not fully tightened from the manufacturer, or may have gotten loose through repeated refills.
2) Look at all the inner seals and gaskets to make sure they haven't become dislodged.
3) Make sure that you screw the tank into the base tightly. If it's not tight, it may leak.
4) When you screw your clearomizer into your battery, do not overtighten--screw it in only until it makes contact--no farther, or you may push the center post in too deep and cause all kinds of problems, including leaking. When the draw becomes tight or the taste and vapor production begin to diminish, replace the coil. This will happen sooner (even as soon as one day of heavy use) if you're using dark, viscous, or very sweet juices. The old coil can be cleaned and dry burned.
and
5) Make sure you're not getting juice in the center tube when you're filling--this will cause your eVod to leak like a sieve. If some juice gets into the tube, close the top cap and blow gently through the clearomizer to get rid of any excess
eliquid.
Good luck!