I bought a 2006 Tundra without the tow package. I now want to install a transmission oil cooler in front of the radiator like the ones that come with the tow package. Has anyone done this? The coolers are cheap enough. My main concern is that the 2006 has a sealed unit so how do I add the additional coolant needed for the increased capacity? And with no dipstick how do I check the new level? Thanks for any help!