Stripped transmission drain plug - Ford 4100

[Other Bob]

I bought an 80's Ford 4100 diesel a couple of years ago and I need to change the transmission fluid. However the plug is stripped, so I can't get it out. It's the type with an inverted 1/2 inch square which was almost completely rounded. I couldn't get any bite with my 1/2 breaker bar so I ordered some extractors. The plug seems to be soft metal as the extractors seem to get a little bit of a bite and then just start eating away material.

I'm not sure what else to try, I was going to try and collapse in the sides so that the threads would be loose but it sits almost flush with the transmission housing so I can't really get much forse from the outside.

Any suggestions?

 

[Diggin It]

Oh No!!!! Here we go again, another 1,000 posts .....


Sorry Bud, inside joke about a stuck drain plug thread .....

As I recall, he had to drill the plug mostly out before he could extract the remains.


Here it is .... start towards the end and read backwards...... https://www.tractorbynet.com/forums/parts-repairs/393632-rounded-off-drain-plug.html

 

[dragoneggs]

Oh No!!!! Here we go again, another 1,000 posts .....


Sorry Bud, inside joke about a stuck drain plug thread .....

As I recall, he had to drill the plug mostly out before he could extract the remains.


Here it is .... start towards the end and read backwards...... https://www.tractorbynet.com/forums/parts-repairs/393632-rounded-off-drain-plug.html

Specifically, posts #1903, #1910, #1912, and #1923

 

[TractorGuy]

NOOOO!

LOL

Maybe try one of these.

Advance Auto Parts - Down for Maintenance

 

[Other Bob]

Thanks for that link... I think. I had to go back a good number of pages to even find anything related to actually getting the plug out. I had no idea drain plugs could cause so much conversation. Sounds like his was more of a standard plug with a hex head. Mine is more like the picture:


That being said I think I'll have to end up doing something similar and drill it out. I don't have a bit nearly as big as the plug, I'm guessing it's close to an inch in diameter. I was thinking about using a small bit and drilling holes in a v - pattern to make a pie shaped section that I can knock out and then try collapsing the rest. My fear is damaging threads or cracking the housing.

 

[Diggin It]

Mine is more like the picture:

You mean yours is SUPPOSED to look like that, right?

My fear is damaging threads or cracking the housing.

Yeah, that was a concern over there too.

 

[Jstpssng]

All that he said was "Drain plug" and everybody started having flashbacks. Good luck, I hope that it doesn't take a year and 2000 posts to get it out.

 

[dragoneggs]

All that he said was "Drain plug" and everybody started having flashbacks. Good luck, I hope that it doesn't take a year and 2000 posts to get it out.

Oh... we are much smarter now after that learning experience and as such, better able to help!

 

[Other Bob]

You mean yours is SUPPOSED to look like that, right?



Yeah, that was a concern over there too.

Yes, mine is supposed to look similar to that but the square hole is almost round.

 

[Diggin It]

Oh, so you need a round peg for the square hole.



Hey, Peanut Gallery .... is this a candidate for welding? Piece of steel rod somehow, in the hole, then welded to the surrounding surface of the plug? Maybe bent like a lug wrench?

 

[dragoneggs]

Oh, so you need a round peg for the square hole.

That's what TractorGuy was proposing! :thumbsup:

 

[TractorGuy]

If you post a photo of YOUR drain plug we might be better able to make suggestions.

When I search for a drain plug for a Ford 4100 they all come up showing straight threads and a external hex. I hope someone didn't replace a straight thread drain plug with a pipe plug.

 

[dragoneggs]

I hope someone didn't replace a straight thread drain plug with a pipe plug.

That would surely explain things!

 

[CoyPatton]

A pipe plug explains a lot, the biggie is dissimilar metals and thus corrosion. A big possibility of galvanized if it is a pipe plug, be careful welding as galvanized metal can and does give off toxic fumes.
You may have some luck with a hammer and chisel, the jarring action may loosen the the corrosion as well as turn the plug. I would go to a NH dealer and get the correct plug before going very much further.

 

[Mat4644]

Take hardened square key stock the next size bigger and grind the end to a slight taper. Keep the corners sharp. Tap the hardened key stock into the messed up square hole. Fit should be tight. Custom fit extractor that we've used many times.

 

[WranglerX]

Is the plug steel or some alloy?..... IF steel weld a nut onto it?

Dale

 

[Other Bob]

Take hardened square key stock the next size bigger and grind the end to a slight taper. Keep the corners sharp. Tap the hardened key stock into the messed up square hole. Fit should be tight. Custom fit extractor that we've used many times.

Too late on using something square, I tried a male 5/8 bolt extractor and it's pretty much eating at the metal and the hole is pretty round at this point.

The old one looks like this just found it on a parts site for the ford 4100. I'd already bought a new one last year and then put off changing it when I found the old one stripped. Just went out to the shop to dig it out and it's almost the opposite of what's in there.
Don't remember where I purchased it from, one of the online tractor parts places. Both are listed as 3/4 - 14 NPT.

I guess the good thing is if it's the correct plug it's probably not galvinized and therefore might be able to weld a rod or old lug wrench to it. I don't think the welding would hurt the cast housing as long as I just weld a little at a time so that I don't heat it too much.

 

[WranglerX]

Too late on using something square, I tried a male 5/8 bolt extractor and it's pretty much eating at the metal and the hole is pretty round at this point.

The old one looks like this View attachment 671658 just found it on a parts site for the ford 4100. I'd already bought a new one last year and then put off changing it when I found the old one stripped. Just went out to the shop to dig it out and it's almost the opposite of what's in there. View attachment 671657
Don't remember where I purchased it from, one of the online tractor parts places. Both are listed as 3/4 - 14 NPT.

I guess the good thing is if it's the correct plug it's probably not galvinized and therefore might be able to weld a rod or old lug wrench to it. I don't think the welding would hurt the cast housing as long as I just weld a little at a time so that I don't heat it too much.

You can try the weld trick, might try sacrificial socket wrench extension...But get a wrench on it while steel is hot and metal is relaxed....

Dale

 

[dragoneggs]

I would definitely try Dale's suggestion.

 

[Mat4644]

Heating the plug causes it to expand. Might make the fit tighter. Maybe letting cool down after welding better. Just the expansion and contraction of the metal might break bond.

Hammer and small sharp chisel sometimes work. The impact action often breaks things loose. The internal expanding extractors work great on broken off pipe. Don't know the condition or depth of the hole if reasonable.