Help with stripped transmission pan drain threads. (1 Viewer)

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Kernal

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Dec 10, 2007
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(Probably should've titled the thread "Help needed with---)
While changing the fluid in my transmission pan I think I may have crossed threaded the pan threads, not sure. The plug went in OK using finger pressure for the first two turns, then got stiff, so I backed it out and tried a few more times, each time it got hard to turn after a couple of turns. I then used a small ratchet to tighten the plug; after a quarter turn not using much force it freed up and seem to tightened up normally, but when I got to the point where it should get very tight, it just continued to turn, but still with some resistance. It is not leakiing. Not sure if I should drive it that way. Is there some temporary way to keep the drain plug from loosening up until I can do a permanent fix?? Any suggestions, other than a new pan? Drill and tap the hole maybe? (Never done that myself)

Anyone use the Timeserts before for this application, or are they just for aluminum pans??

http://www.timesert.com/html/drainplug.html


I leaving on a long trip tomorrow :bang:
 
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you can probably have heli-coil installed at minimal cost. I have never installed one, so I don't know how much skill is required. You can remove the pan and have a machine shop i.e. NAPA install it for you. It also may be possible to find a plug that is slightly larger and tap a new hole. You probably want to remove the pan for this too. Metal shavings can do a lot of damage to a transmission.
 
Yeah, that was my concern also (shavings). I was looking for a quick temp fix as I am going out of town tomorrow. If the drain plug is still dry in the morning I might just head out on my planned trip and check for leaks around the drain plug everytime I stop.
 
If you do that, I would wrap the plug with some teflon tape and maybe the threads will tighten up a bit. You can also add a small bead of JB-Quick to one side of the plug to lock it in place. Just a small amount you can knock off with a putty knife.
 
john_eckels: Was trying to avoid pulling the plug right now afraid it might not go back in and to save about $35 of Mobil 1 synthetic I just put in. It does not appear to be leaking after sitting overnight and after a drive this morning. I just get back from the parts store, but grabbed some of that two part epoxy putty in a tube that turns rock hard after you mix it. Idea was just as you suggested, put a dab on one side of the plug and pan?? Didn't know about the JB-Quik, is that more of a liquid?
 
If this is a 343 transmission (95-97, you did not state what vehicle you are working on) what has most likely happened is the bung has broken loose from the pan. The correct repair is to replace the transmission pan. Alternatively you can remove the pan and attempt to weld the bung.
 
CDan; Yes, mine is a 1996 FZJ-80 with the 343 auto tranny. Yeah, was afraid I might have to go for a new pan. So the bung is a ? pressed in threaded part where the drain plug goes?? Is it possible to fix the bung? Either way looks like I'll be dropping the pan when I get a chance.
 
Kernal said:
CDan; Yes, mine is a 1996 FZJ-80 with the 343 auto tranny. Yeah, was afraid I might have to go for a new pan. So the bung is a ? pressed in threaded part where the drain plug goes?? Is it possible to fix the bung? Either way looks like I'll be dropping the pan when I get a chance.
Click to expand...

AFAIK, the bung is sort of spot welded on and the spot welds are really rather weak. My suggestion is simply replace the pan and get it from Dan or John. The reason I say this is yes, you can re-weld the bung there BUT you've gotta sand off some paint, spot weld the bung so its threads and the pan's threads are all aligned, repaint the pan with paint that won't dissolve in the ATF, let that paint properly cure (translate - time w/o running rig) and then replace the pan. I think the thing was sub $100 when I bought it back three years ago. Much easier and less expensive (translate - what's your time worth?) to R&R, than to repair, in my opinion. HTH. :cheers:
 
turbcruiser; if the price is under $100 US, then it may be worth it just for the time and convenience as you say. If it is a spun bung then can I assume that the plug will not drop out, just maybe seep a bit at worst?? The drain plug is still much more than finger tight but less than full tight and not leaking so far.
 
This is a picture of the inside of the pan plug so you can get an idea of how it is made.

Bill
 
Photoman; thanks for the photo, it helps to see what/where the problem is and what the fix might be.

Turbocruiser/anyone:
I have access to an arc welder, but have never used one before. Could you just touch the bung with the welding tip with the drain plug in place, that way it is already all lined up?? Wonder how it actually seals? It looks like the bung is just sitting there, or is part of the pan molded up to fit inside the bung??
 
Kernal said:
turbcruiser; if the price is under $100 US, then it may be worth it just for the time and convenience as you say. If it is a spun bung then can I assume that the plug will not drop out, just maybe seep a bit at worst?? The drain plug is still much more than finger tight but less than full tight and not leaking so far.
Click to expand...

The plug will not drop out, even if you want it to, which is how I found out my "bung had spun." It will do what I call "leak" which means after parking all night, you'll see some small amount on the ground (I'd estimate 3.5ml). I do NOT do leaks (especially something like a tranny with no "low-oil-light" feature) so replacement was mandated. Actually I think that I broke the bung loose as I was loosening the plug; my pan didn't leak one drop as far as I remember until I went to loosen the plug to drain and fill and that was when the plug wouldn't come out ... I realized I had spun the bung and then noticed that it leaked ... so either I spun it while loosening it OR the threads of the pan/bung were strong enough once to hold the spec'd torque but not strong enough twice if the bung itself broke loose. HTH. :cheers:
 
Agree with not wanting to lose all the ATF with no warning, that could be a bad day. If I see no leaking at the drain plug I'll let it ride until I get back from my trip. Hope the new replacement pans have a "better bung" than the originals as I used a small 3/8 ratchet when tightening the plug and didn't power drive it.
 
If you have never welded before I would not make this my first experience. The bung metal is thicker then the pan material so a person would have to get penetration in the pan material without burning through. For your information the pan material is about .066 inches thick, not the best thickness for stick. In addition a person would have to be careful welding as to not warp the pan and make it harder for the flange bolt to seal. It can be done, but........
Another option is to take the pan off and drill out the bung. Buy a nut certs – nutserts – rivnut – rivet nut from NAPA or many other sources, put some RIPG (goop) on the nutcert, and squeeze it in. They make them with serrated edges so this will keep them from turning again. Ideal for this application. They also make them with or without flanges on them. You do need the proper drill size for the nut cert and the material thickness (.066). If you do not have an install tool many auto parts will rent or lend you one. You can also just make one from a bolt. The nut certs come in many different threads. If you wish to stick with the stock thread it is M10 X 1.50. I would get a longer flange bolt than the stock one; say 16mm or 20mm to make sure it would catch the threads of the nut cert. Lastly, some goop or a copper washer could be used on the new pan bolt if worried about a seal.
Another way to repair this is to weld a nut on the outside of the pan. The outside is more accessible to weld around the nut. The various goop or copper washer ideas could then be used to insure a good seal. I would remove the pan to do this as it is not helpful to melt the mesh trans filter.
I don’t know your level of skills, so maybe none of the above will be helpful.

Bill
Trans-pan-nutserts.jpg
 
the quick fix you did (sealing the drainplug with steel epoxy) will do for a long time. probably till your next flush. i used epoxy steel on my gas tank drain plug. just tilted the car to keep the plug dry then let the epoxy set. but getting a loose thread might mean you have metal shavings in your pan now? i hope the magnets catch it. i put 2 extra magnets in my pan. total of 6
 
cruiserdan said:
If this is a 343 transmission (95-97, you did not state what vehicle you are working on) what has most likely happened is the bung has broken loose from the pan. The correct repair is to replace the transmission pan. Alternatively you can remove the pan and attempt to weld the bung.
Click to expand...

This happened to me a year ago and replacing the tranny pan was the correct way to go about it.
 
I have the same issue with my rig - I ordered a new pan from landcruiser parts LLC (discontinued by OEM). Right now bolt is in, hand tight, but just spins when I try to wrench on it either direction. The fluid is barely leaking — enough to feel a little greasy but not dripping. Any tips on further sealing the plug from outside before the new pan comes in? RTV vs epoxy? I’m planning on checking fluid level every fill up til I get the new pan.
 
@tedtonks87 :

Welcome to Mud. This is a 14 year old thread resurrection, but here goes.

For a short term fix you could use a sealant designed for transmission fluid, slather it on the plug threads and under the washer, install and hope for the best. The trick is getting the threads dry, hard to do with the pan still on the vehicle, maybe let it sit overnight with the plug out.

What I ended up doing 14 years ago (short term fix) was to sand an inch around the plug to remove paint (I couldn't remove the plug as it just spun with the bung) then pushed a two-part epoxy putty over the drain plug

For a short term fix just about anything will work to slow down or stop the drip.
 
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