Somone take me off the brain donor list ...>

Well I bought my 94 5.0 with about 126k on the odometer, a couple weeks back I decided it would probably be wise to go through and change out all the fluids. I flushed the radiator coolant, changed out the gear oil in the diff, changed out the oil (of course while it's in the air) and also changed out the manual trans fluid.

Here's the problem. Ford calls for Mercon automatic trans fluid, so I drained all of the old out, reinserted the lower drain plug to torque spec, and pumped in the new fresh fluid to spec. I reinstalled the upper fill plug to torque spec. I've driven the car say 100 miles or so since, and noticed the trans fluid has been leaking a bit. About a silver dollar sized puddle on the floor of the garage. So tonight I put her up in the air, and noticed a bunch of grime mixed with trans fluid coming from the area of the upper fill plug. I grabbed to carb spray, cleaned the area up and about died when I saw where the upper fill plug is on the trans housing is about a 3/4 inch crack! Definately the source of the leak. Dammit!

So... in lieu of changing out the trans what can I do? Mainly this crack is limited to the area just on the side of the fill plug facing the back section of the car. I imagine some may have had this happen before. Any info/ideas on a fix would be great.

Here's a pic.

View attachment 362895

Well I think it's fixed. Two days ago I put the car up in the air, drained all the fluid out, and cleaned the crack/thread area with brake cleaner. I used some sandpaper that came with a soldering kit I've had for a while, and sanded the affected area on the outside, roughing it up pretty good. Laid down a nice bead of JB Weld over it, and smoothed some RTV on the inside portion, and let that all cure for 24 hrs. Then, I filled the trans with mercon, put a layer of RTV around the threads on the fill plug, and carefully tightened it down. I added another bead of JB on top of what I did the night before for safe measure. Another 24 hours for everything to cure.

Tonight I took the car out for a nice 30 mile drive, ranging speeds, mainly highway. After letting it sit for a while, no leaks! We'll see what's under the car in the morning.