I was checking the tranny fluid level on my 2000 F-250 7.3L 6-speed and someone must've WAYYYYYYY over-tightened the fill plug. I had to use a 1/2" drive breaker bar w/ 3/8" downsizer on it to break it loose. I was threading the plug back in and heard a popping noise. I thought it was the O-ring tearing b/c I took the plug back out and the O-ring was torn. I found a new one in my shed and put it on there. I drove it the next morning and then got under there for something B4 my wife and I went out again, and noticed it was leaking a bit from the fill plug. Upon further inspection I saw 4 very small stress cracks around the fill plug spaced evenly at 12, 3, 6, & 9 O’clock. My buddies that have worked on a lot manual trannys have ever seen this happen. Its not super bad, but its enough that it needs something done. Its dripping a few drops every few minutes. Plus its not like an auto where you can just dump more in from under the hood.


Has anyone experienced this, or heard of a good reliable fix without pulling the tranny and replacing the whole housing? This is really worrisome to me! I put JB weld around the cracks, but don't know if that will hold and if it does I'm afraid it will crack again when I take the drain plug out again.

Also, should the drain plug have a gasket or O-ring on it even? I don't remember seeing them on any other tranny's I've done.

 

There are thin O-rings on the last thread of these plugs on my tranny. The area around the fill plug is pretty beefy, it probably has a 1/4 inch raised bung around the plug itself. I can't imagine the force it would take to crack the aluminum, but I guess it can be done! The first time I opened both plugs, it was really tight. I had to use a large torque wrench with a 1/4 adapter and the plugs did "pop" free, but now, they are fairly easy to take off with the torque wrench. Plus, I tighten only until there is no seepage, cold or hot. I guess you could MIG weld an aluminum washer of the appropriate OD/ID on top of the cracked bung. (Easier than TIG welding...)

 

Thanks N578md. Unfortunately it is definitely cracked, and still leaks after i took the O-ring out. I called a local transmission shop and the guy said the same thing you did! He said he's never seen one do that and couldn't imagine how it could happen, but mine did! Who knows how it was done, but its done so now I have to fix it, or have it fixed. I think aluminum welding would be a good option, if no other reasonable fixes work. Welding would bethe most permanent but I usually have bad luck having other people work on my vehicles, especially something weird like this. I wonder if a coating of pipe dope would work?

 

I'm not sure if that would hold very long. Those tranny's get real hot so maybe with the hot/cold cycles, the dope might crack and allow it to leak again. You must have some good welding shops around you. I've had poor luck with filling in cracks by welding them but much better luck with welding new (and similar) metal on top of the cracks. I don't know, it depends on how much you like the truck and how long you plan on keeping it.

 

LOL, OK I'll look into having them welded. I love the truck and plan on keeping it a long time (course I say that about all my vehicles but maybe I'll keep this for more than 2 years!)

 

Wow..i think thats a freakish thing to have that happend. Having it welded is most likely the only way to fix it vs. getting a new tranny case. But if you find a welder that will weld it, get down on paper that if somthing goes wrong your not stuck there with your thumb stuck somwhere the sun down shine and a big gapping whole in the side of your tranny. Welding alum. is tricky stuff if you DONT know what your doing. Hope you get-r-done, i HATE it when my truck leaks....anything.