F'd Up - Stripped Transmission Fill Plug

Same problem for me. Had my local mechanic install a trans cooler last month. They had to replace some fluid lost. Went and did a drain and fill this weekend and half the threads came out with the bolt. They over torqued it.

I'm taking it back to him and hopefully he can fix it. What did you end up doing?

 

I ended up doing this from this video.

https://www.youtube.com/watch?v=kDyBi8QuRng

There were still a few threads left in the housing extension at the end due to the original crush washer's thickness. Got a new filler cap. I applied some Permatex gasket maker to the new cap and carefully hand-tightened to seat it on the few remaining threads and then torqued it to about 12 ft-lbs. I did not reinstall the crush washer. I've only recently done this so I need to recheck for leakage but so far I haven't seen any.

 

Probably what I'll have to end up doing. When I pulled the fill cap off there wasn't a washer. Like I can see threads but I tighten it down and gets to a point then just keeps turning. I bought one of those neoprene expanding plugs but the 19mm won't fit the hole. Not sure if I want to risk using one of those because of degradation later on.

 

someone said it earlier, boat bung plug, they make all kinds, and with oil and gas in the bilge, yes, they degrade, but it takes YEARS...easiest solution

 

Best long term solution? I mean I'm kind of hesitant on them. I put a snap clamp one on today and it doesn't leak at all. I'm just afraid of the thing falling out in the future. Sucks. Wish I could reverse time.

 

This is why I went the gasket maker method. The plug is basically glued in place but still removable in the future. I will only open it every +50k miles which at this rate for me is about 5 years or more.

 

How long have you had it in for?

 

Is it possible to tap the hole to the next size up?

 

I stripped my transfer case fill plug earlier this year. Depending on how big the plug is, local shops might not have that sized tap. If they have a tap that's big enough and are willing to do it it should work just fine even if it's MM or Standard. Even the local semi truck repair shop didn't have one big enough

 

The I measured the plug and it's like 17 or 18mm. I'm assuming it would need to be a 19mm tap.

I can't help but have this dreadful feeling about my truck all the time now. I've put so much time and money into it. Sighs.

 

I feel ya. At least the transmission can have a new pan installed. The very skilled and reputable trans shop said they could not replace that half of the T case. Had to replace the whole thing with a new to me/used case! That was a $1300 mistake.

After the T case was installed my trans developed a shutter. I got opinions from 2 shops and both said the trans was on its way out. That was another $2k.

I had 5 new tires and new shocks installed last year. Guess what I found a month or two ago. A hole in my frame by my trans support brace!
With 191k miles, mechanically my truck is solid but not the frame...

 

Problem is, this isn't the pan. It's the case where you put fluid into. Lol

 

That chunk even has the anti rust wax stuff on it. RIP

 

Oh shoot. I misunderstood

Is it the fill or drain plug? If it's the fill then one of those rubber expansion plugs might seal it good enough.

 

Yup I Fluid Filmed the frame since I got it. Not only mechanically it's sound but the body is in great shape and the interior is decent shape. No rust on the lower door panels, minimal on the floor pans and the rocker panels are solid. Rear bumper is rusting out but that can be easily replaced.



Sorry I hijacked this thread

 

A heli-coil worked for me when i stripped the atf drain plug. Just had to make sure it was trimmed short enough on back side of pan. New plug was cheap from dealer too.

 

The fill plug is not going to be easy to repair. It’s a big plug and not easy to get to with taps or thread repair tools.

I seen this happen before. The guy used an expanding rubber expansion plug.
Like the ones you use on the engine block. Some guys call them freeze out plugs. It’s janky, but it worked.

 

Torque wrench’s on fill plug? No! Tighten it like your oil filter.

 

The problem is, the specs are for dry threads. Most people don’t clean and dry the threads. The plug threads AND the fill port threads.

But I agree. Once the gasket is crushed, snug is good enough. You don’t need a torque wrench.

 

It's been on for about a week and a few hundred miles but so far no leaks.


It was a real bitch and a half to try to get that photo with my trilogy of skids and cat converter extension plates in place. I cleaned it with brake cleaner before applying the Permatex solution. No evidence of oil. There definitely was oil before I did this.

As others have mentioned, retapping this is a whole other ordeal. The working space is super confined and awkward so the easiest way would be to take it out to do. Plus you'd need to drain and replace all the fluids to guarantee that you get the newly tapped threads out. Quickly spiraling into a larger project for a small problem.