Hi, I posted this on NASIOC, but I thought I would throw it out here as well. Well - I stripped the fill plug when replacing my transmission fluid today. I read through the other similar post about someone that bought a longer fill plug to catch the threads further in. My question though is - I don't think it completely stripped, I felt it give and then I stopped and I can thread it back on and it holds...albeit with much less torque. I put some thread tape on it before putting it back in, but I realized that I won't really know if it is leaking because the only time it would leak is when I am driving. So - is there a lot of pressure generated inside the transmission when driving? I don't want to have any issues, but I don't know what the next step would be to machine a new plug that would work. Any ideas would be GREATLY APPRECIATED!!!! Erik
Do you have a thread restorer set? Not a die set, a thread restorer set? Snap on sells individual sizes for a few bucks with free shipping or Craftsman sells the exact same pieces in a 48 piece kit for anywhere from $40-$50 on sale. Instead of cutting new threads, it forces the threads into their previous position and can save old nut/bolts/plugs/threads from having to be thrown and replaced with new ones. Looks like sears is currently out of stock. Kastar/Lang is the oem for this tool set (both snap on and craftsman rebrand it, as well as about 20 other well know tool brands-not kidding) This tool seller is located in MN and if you call, you can do a in warehouse pick up. Says they have it in stock and just as cheap as the craftsman set would be on sale. http://www.tooldiscounter.com/ItemD...HSxsMD2myX2yb4_lfUn7xfPTfkKrPIrAYdBoCbGzw_wcB Snap On- click on sets/members and you can order the individual pieces for anywhere form $2-$6 if you just want the size you need (with free shipping too!). It ships from Wisconsin or Chicago usually, so it takes anywhere from a day to three days to arrive usually. https://store.snapon.com/U-S-Metric...it-Master-Rethreading-U-S-Metric-P641094.aspx
Fantastic! I love the thread restorer idea. I assume that I would just buy a new filler plug and crush washer correct? This is a lifesaver if it works the way that it sounds. Thank you!!!!!
Shancaldazar - do you have the link for the Craftsman set? And how easy it is to do this myself? Do you think that there will be some metal shavings that get into the transmission when I do this? Does it restore the female threads? I don't want to restore the plug threads, just the transmission plug hole threads. I would buy a new plug and crush washer. Also - the stock plug size is M26x1.5x16 - I don't think I see that particular size in the Kastar set? I will browse through the Snap-On stuff to see what I find. Thanks for your advice so far...any thoughts for my questions would be greatly appreciated! Erik
I can't find the craftsman set on their website anymore, which makes me think that they may have discontinued it (like everything else good they produced). This will produce a small amount of metal shavings if the threads are really bad (it will be a fine powder). If they are just a little displaced, usually no metal is produced. M26X1.5 is quite a large size, so that might hard to find the proper thread restorer. A quick search isn't yielding much for the internal thread repair of that size. The files included in the kit can repair the drain plug (they are rated by thread pitch, so they can restore any size external thread of the same pitch). I large tap may have to be used for the internal threads. Since it's aluminum, a high carbon steel tap should be fine, but when using a tap as a thread restorer, you want to try not to cut new threads, just force the old ones back into place- old worn out taps actually work great for this if you can find a worn out m26x1.5 tap.
The thing is, in aluminum, you're probably going to have sheared off the threads rather than simply distorting them, so a tap/restorer isn't going to have a lot to work with, plus just finding on in M26... You might be able to do a helical insert, but that would involve drilling & tapping and a lot of potential for material to get in the transmission case. Plus they're expen$ive. And might be too deep and hit stuff inside the transmission. I'd try and find a slightly longer plug to catch deeper threads and use some RTV. If that doesn't work, I'd look to find someone to TIG weld a bung onto the exterior of the transmission.
Thanks Mark - that is good information as well. I am actually questioning the specs that I laid out earlier as they appear to be for the drain plug which is significantly bigger than the fill and transmission pan drain plug. I think it is either a M18 or M20, but I am having a deck of a time finding the specs online! I may just call the Subaru dealer... And my dad told me about the helical and my first concern was he extra metal shavings getting in the transmission, so I don't know how comfortable I am with that. If I could find the actual specs of the bolt then I will try to find a longer one with some RTV. That seems like the best solution. Not to try and find one while I am on a business trip in China. Oh goodie. Thanks! Erik
If it's only an M18 or M20, I probably have a tap (up to M24, i think). If you were to do the helical insert, you would put grease on the drill bit and tap and go slowly and clean the shavings off (and reapply grease) often, and that would minimize what ended up in the transmission, but I have no idea how thick the casting is there.
there's probably already some metal floating around in the case, it's a subie trans after all. I wouldn't be too concerned with that if you need to helicoil
I've been periodically searching for a good thread-restorer kit, and this is exactly the info I needed. Thanks!
OK - I bough a new fill plug (dimple) and while it is better it is still not perfect. However, I found a M18x1.5x21 transmission drain plug bolt that is designed for a 2005-2006 Evolution. Do you think this would work? The STi transmission housing has threads deeper in so if I can catch those with a longer bolt it would be perfect! https://www.rallysportdirect.com/sh...-dimple-magnetic-transmission-plug-m18x1-5x21
I'd measure the depth of the threads and if it's 21mm or greater, I'd go for it. Just want to make sure you don't protrude into the casing and hit something. If you can get all four wheels off the ground and rotate the engine by hand while in gear afterwards to make sure there's no interference that would be a good thing to test also.
Yes - I think that is a good idea to measure it. And how would I manually rotate the engine? I will have all fur wheels off the ground. Do I just turn a wheel?
Typically you'd use a breaker bar with a socket on the crank pulley. Easier if it's a ratcheting bar.
Haha - of course. There is someone else on NASIOC that had the same issue, and he had a custom bolt made that was M18 x 1.5 x 24 versus M18 x 1.5 x 21 and he installed without issue. I think I will be fine but will check just to be sure! http://forums.nasioc.com/forums/showthread.php?t=2679405&highlight=inner+thread+stripped And ultimately - I am confused as to why Subaru would design the bolt metal to be stronger than the transmission housing metal so much that it strips the housing before stripping the bolt. Everyone I talked to said that most products are engineered to strip the bolt first to prevent expensive issues like this happening. If it weren't for the extra threads further in I would be tapping to a larger size!
