I used a simple rachet without the sockets. That square piece fits right into the bolt. It sounds like you might of been trying to loosen something else.

 

Nope, passenger side. lower part of transmission, square head plug that accepts a ratchet, mine just will not budge.

 

I have a 90 accord 4 cyl auto. Whats the best way to change the tranny fluid on it? Does it have a filter?

 

Use a breaker bar and slip a nice 2' or 3' piece of black iron pipe over the breaker bar handle to lengthen it and get some additional leverage. I've used a pipe from my pipe clamp collection in the past (I also do woodworking). This worked great for the crank pulley on my '85 Volvo 240 when I had to pull the crank pulley to change the timing belt. You'd be surprised the leverage you can get by adding a couple of feet to a breaker bar! You can also sometimes "borrow" the handle from a hydraulic floor jack if you don't have any pipe handy.

If I couldn't loosen it with 3' or 4' of breaker bar + pipe, I'd put some gentle heat on it. Personally I use a propane torch but I'm VERY careful about using it near the engine compartment. Watch for rubber hoses, CV boots, and fuel lines! I would just play the tip of the flame over the bolt for maybe 10 seconds before trying to loosen it again. Sometimes the differential expansion between different metals (aluminum tranny case and steel bolt) can work for you.

One last point, and please don't be insulted by this because it's bit me in the past, more than once. Be sure you're loosening the bolt and not tightening it! Remember, lefty-loosey, righty-tighty!

Good luck, and please be careful if you use the torch (maybe a borrowed heat gun would be a better idea!).

Lou

 

Another thing I've had good luck with is using a breaker bar and tapping on the breaker bar about mid length with a small sledge until it starts to move.

 

it had crossed my mind that it may have been left hand thread, but it wouldn't budge for anything in either direction... Guess i'll keep trying

 

the plug on my 99 v6 auto was impossible to budge,so we got under put ratchet in hole and commenced to kick living crap out of it....lol soon came loose..
so is there a proper fill hole on my car and where is it cos it is a real pain putting it in the tiny dipstick hole....

 

I've used leg muscle to loosen hard-to-turn bolts by laying on my back and pushing the breaker bar with steady pressure using my foot. Legs > arms. Of course I don't go 'round doing that on 1/4" bolts. As jschmid mentioned, tapping with a hammer helps too. Tap gently and from different angles. You might try a little penetrating oil too.

BTW, when you put in the ATF, make sure to NOT overfill.