Hit drives straight off fairway, slice off Tee

[ryan60600]

I use my 3 wood for all drives because I find it easier to hit that my driver. I'm very consistent with hitting my 3 wood off the fairway, it goes straight and decent distance.
However when teeing off, I commonly slice it to the right.
Previously I used to have the ball halfway higher than the tee, I've started lowering my tee so the club is about half way above the ball and I can now get some drives that go straight, but was just wondering if anyone knows what this could mean in the context of my swing e.g the reason why lowering my tee is making my shots go straighter, and why I can hit it straighter off the fairway?

Thank you

 

[bobmac]

Normally, lowering the tee can lead to a fade so a bit tricky to tell why.
If you could post a youtube clip of your swing that would help