I have a 1986 Ford F-150 two wheel drive, and I have 63,000 miles on it. The original owner passed away, and I have no idea if he ever changed the differential oil or not, but whenever I drive the truck, it has a strong hot smell that seems to come from under the truck. The problem I am having is that I cannot get the plug to budge. It is one of the plugs that have the 3/8 square to put the 3/8 extension into. It is rusty, as would be expected from being 25 years old, and I cannot use a torch on it since the fuel tank is only 2 inches away from the plug. I thought about maybe there is a way to get a new cover, and put a drain plug into it, but the bolts on the original are also very scary looking. I am almost positive that I will end up breaking one or more of them trying to remove them. I am open to any suggestions as this is a problem that needs to be addressed before winter hits. I soaked it with PB Blaster, and it did not work. I have not tried anything else as of yet.

 

If the 3/8th square hole is not rounded out then take a screwdriver and clean it out real good so the extension goes in all the way get a cheap throw away extension and grind it flat on the end so the sides go all the way in smack it with a hammer a couple of good whacks then use a long breaker bar or a cheater pipe over the handle of a ratchet and don't be afraid to put some force on it. AS a last resort get a 1/2 to 3/8 adapter and use an impact wrench. I don't think rust is the problem its just to dammed tight

 

Thank you bubbabud, I will do this in the morning, and let you know how it goes. I appreciate the idea. I really hope I don't need an impact wrench, but I think not. The extension idea is a good one because one of the problems I have is that there is a lot of wiggle room just putting the extension in the way it is. Plus using the ratchet leaves more wiggle room, so I think the breaker bar may help. Thank you!

 

I've come across this many times before and it's not fun to deal with. As bubbabud mentioned, get a small flat head screw driver and clean the inside of the plug really well. Instead of using an extension, get a 1/2" drive with a 1/2" to 3/8" adapter (this gives you stronger leverage over the plug). You should be able get that in the plug firmly and use as much force as you can to break it loose (if you're able to get a breaker bar on, do it). The extension idea can work but you lose stability when you don't have direct contact between the tool and the plug and this may cause you to strip/round the plug.

You may even try using Seafoam and soaking the plug as much as possible and then try to remove it. I've never personally used Seafoam before but many mustang enthusiasts have told me to use that stuff on the spark plugs before trying to remove them. They say that it really does a good job at loosening up the threads of the spark plug from the block so they don't break. GL!!