Rep Power: 0

My civic is a 2003 manual sedan ex. I got this car about 10000 miles ago and I figured I should change the transmission fluid. I've been able to get the bottom 3/8" nut off to drain the fluid but I have not been able to take off the top 17mm nut to fill the transmission back up. I've been at this for hours and it's raining and I'm covered in mosquitos. Until I fix this I don't have a car to drive. I've tried using ratchets right at the nut where the air box would be, tried using a 20" extension and having at it from the wheel well and using a breaker bar, and I even used an air powered ratchet with absolutely no effect. I am beginning to think I need to get my car towed to a shop to have them take it off

 
Rep Power: 142

They are generally fairly tight. Maybe a previous owner used loctite? Using long extensions do limit how much torque can be applied to a fastener. You can usually feel the extension start to flex on really tight nuts/bolts.

Are you sure you trying to remove the right bolt? You should be able to see an aluminum sealing washer under the edge of the bolt head. It should look like this.

http://honda-tech.com/attachments/ho...1138065289.jpg

 
Rep Power: 518

I'd get it from underneath using a 17mm box wrench and some leverage.

 
Rep Power: 208

Breaker bar from underneath!