63 Muncie fill plug

[Frank D.]

What is the "head size" of this square plug ?
Someone munged mine up badly and I can't determine. 9/16" square socket seems too large...which is all I have on hand.

[Harry S.]

Re: 63 Muncie fill plug

Just went to the garage as the 63 is on the lift. Yes, the 9/16 is too large and the 1/2 is too small. I've always used a monkey wrench.

[Frank D.]

Re: 63 Muncie fill plug

Well, my plug was rounded off by some past miscreant and a pipe wrench, nor crescent wrench, nor vice grips have worked - prob made it a bit worse.

Been soaking the darned thing in PB-Blaster for 3 days and no joy... Haven't tried heat yet but that's next.. Also have the Irwin bolt extractors for phase II of the problem...in my experience if THOSE fail the head of the fastener gets completely destroyed.

If so, I'll see if my mechanic pal can weld a nut on it or knows some other trick.
The bolt may be an oddball or metric size..

[Domenic T.]

Re: 63 Muncie fill plug

Frank,
If the damage didn't taper the square then vice grips as tight as you can get them with a few taps with the side of a hammer. I know it's tight and sounds (hammer) like BuBa.
consentrated Heat (not propane) and a shield to prevent damage would do it, but oil will go bang if the fumes ignite.
Dom

[Frank D.]

Re: 63 Muncie fill plug

May be a job for a pro...

Stuff drives me nuts - I have a purportedly original Muncie "W" fill plug which DOES have a 9/16" head and fits perfectly in my 9/16" "square" socket. Which is the plug I will install when (or if) I get the boogered up plug out.

[Joe L.]

Re: 63 Muncie fill plug

May be a job for a pro...

Stuff drives me nuts - I have a purportedly original Muncie "W" fill plug which DOES have a 9/16" head and fits perfectly in my 9/16" "square" socket. Which is the plug I will install when (or if) I get the boogered up plug out.

Frank------


I'm sorry to have to tell you this but my expectation is you'll never get it out. I've "been down this road" with a Muncie. I believe that some form of dissimilar metal corrosion occurs between the iron plug and aluminum case causing the plug to essentially "weld" itself to the case. Trying to use heat might damage the case and I still don't think you'll get it out. I think that what it will take is to drill it out using progressively larger drill bits until the remaining metal is so thin that you can break it out from the threads with a sharp tool.

[Ed S.]

Re: 63 Muncie fill plug

I had the same problem with my 64 - problem is caused by the ferrous metal plug interacting with the aluminum case - left undisturbed for extended periods the two alloys begin to exchange electrons and literally bind themselves together. The bond can be broken - sometimes there is resulting thread damage. I tried everything, heat, freezing, several cycles of it - all the home remedies did not work. I took it to my favorite shop - the mechanic there had a wrench that was about 30 inches long - it was a vice grip type wrench but there was a 9/16 inch bolt near the jaws that tightened them - he secured the jaws on my plug - then put a 3 foot pipe extension on the wrench and pushed down - we heard a snap like a pencil breaking - the plug was free - came out easy after that - and..... no thread damage. I installed a new plug - applied Permatex anti-seize on the threads and now I get under there and back it off a half turn every 5 or 6 months. Good luck.

[Larry M.]

Re: 63 Muncie fill plug

I had the same problem with my 64 - problem is caused by the ferrous metal plug interacting with the aluminum case - left undisturbed for extended periods the two alloys begin to exchange electrons and literally bind themselves together. The bond can be broken - sometimes there is resulting thread damage. I tried everything, heat, freezing, several cycles of it - all the home remedies did not work. I took it to my favorite shop - the mechanic there had a wrench that was about 30 inches long - it was a vice grip type wrench but there was a 9/16 inch bolt near the jaws that tightened them - he secured the jaws on my plug - then put a 3 foot pipe extension on the wrench and pushed down - we heard a snap like a pencil breaking - the plug was free - came out easy after that - and..... no thread damage. I installed a new plug - applied Permatex anti-seize on the threads and now I get under there and back it off a half turn every 5 or 6 months. Good luck.

I have always used anti-seize on this plug. Just removed mine two days ago after about 10 years of doing nothing to it........and it came out easily. So anti-seize is what you want for the new plug.

Frank- you may not get the plug out without taking out the transmission. At that point more options are available. Sear/Craftsman had special removal tools for plugs like this a few years back. You might want to Google this and get some part numbers.......and then go to Ebay or on-line someplace to buy. It hammered on (actually tapped on) the plug or fastener and was very effective at maintaining a good hold on the plug. Then as Ed says, a very long breaker bar or perhaps even an HD impact.

If you can get this removal socket tool to hold, the "hand-held" impact driver Sears and other sold may also do the job. But you need a 1/2 inch drive removal socket on the plug. I bought and used this tool (hand impact) for some stubborn fasteners on my motorcycles in the past, and was always successful. The impact of the hammer blow on the impact tool both tries to move the nut or plug as well as compress/slight deform the threads for a brief second. The combined result is usually positive.

FWIW.

Larry

[Ed S.]

Re: 63 Muncie fill plug

One option that I considered and was prepared to try is to have a sacrificial 1/2 inch drive socket welded on to the plug - mine was rounded and no good anyway - then put the mother of all breaker bars on it and hope for the best. If that did not work the course of last resort was to remove the trans and have the plug drilled out - a welded on socket would not have been an issue if it didn't work. As it turned out my mechanic had a wrench that essentially did the same thing but without welding - see my previous post above on how he did it.

[David B.]

Re: 63 Muncie fill plug

'63 Muncie case print shows 2 optional fill plugs:
# 103868 cast iron
# 103880 steel
Both were 1/2 taper pipe thread plain finish. The head size for both were square width of .563 and a height of .38. Each had slightly different thread lengths and wall thickness. There is a notation: "Torque 10-15 ft. lbs. at trans factory" Do not know if that was a finished product torque. Hope this helps with replacement.

[Frank D.]

Re: 63 Muncie fill plug

'63 Muncie case print shows 2 optional fill plugs:
# 103868 cast iron
# 103880 steel
Both were 1/2 taper pipe thread plain finish. The head size for both were square width of .563 and a height of .38. Each had slightly different thread lengths and wall thickness. There is a notation: "Torque 10-15 ft. lbs. at trans factory" Do not know if that was a finished product torque. Hope this helps with replacement.

Thanks for all the good info, I'm letting the thing soak for a couple of days in penetrate as I'm in no hurry and I do have a set of these which I used successfully to remove seized engine block drain plugs but my experience is, if they fail, the bolt will be munged to the point it renders other methods moot.

I put fresh fluid in 3 years back and it has no leaks so if that becomes necessary it can wait a while and prob do a rebuild as well..

(Joe - I hope you're wrong - we'll see) I'll report back on results (or lack of).

[Tom E.]

[Frank D.]

Re: 63 Muncie fill plug

I'm going to try a few more things but its looking like the fill plug has welded itself in place. The plug is fairly soft metal and anything aggressive chews it up even more. Now I'm gonna ask a Bubba question.

Can I top off the lube through one of the Muncie side cover lower bolt holes ??

They appear to be the same level as the fill plug...or at least very close....that is, if they are "through" holes into the transmission's interior...

[Harry S.]

Re: 63 Muncie fill plug

Don't think so...

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[Frank D.]

Re: 63 Muncie fill plug

Thanks - I'd forgotten...