Tranny Case Leak - ATF

I have my tomos. It has a rather major leak coming out of the drain screw. I know that it was somewhat stripped so i put i na new screw with smaller threads. I recently toook it out and added teflon plumber's tape to it [pretty thinck] to try and fix the problem but this did nothing. Im thinking on sealing off the thing permanatly but I dunno what to do that with if i do that...what are your suggestions?

Re: Tranny Case Leak - ATF

Edward Edwards /

I think sealing it off would be a mistake, why don't you tap new threads & install the proper drain screw? You will be better off in the long run by doing it right.

Re: Tranny Case Leak - ATF

ped58 gave you the best advice. But if you must plug the hole do it temporarily.

Clean the bolt and the hole and the area around it. Go get a tube of silicone gasket maker at an auto parts store. Coat the surfaces and put the bolt in. If the fit is very loose, use something like masking tape to hold it in there. Whats left of the threads will hold it in there pretty well.

Silicone doesn't stick all that well. The surfaces must be absolutely clean. After cleaning use a bit of fine sandpaper and then wash with alcohol and let dry. Don't get any oil on there, not even the oil from your fingers.

Another thing is silicone hardens from the outside in. It seems cured after a few hours but it's not. Give it at least 24 hours to cure. 48 is better. no kidding.. take no shortcut here.

Silicone will resist temperatures up to about 500F and is impervious to auto fluids like gasoline and oils.

The next guy who has to work on your bike wont be happy about having to scrape the stuff off and fix it properly but at least it will be possible to do without breaking something..

Re: Tranny Case Leak - ATF

ok yea i was going to do it temporarily....i think the silicon will be the best idea....thanks

oops.. silicone and gasoline


As far as this transmission case repair goes, silicone is fine..

but i just learned that silicone is not recommended for continuous use with gasoline, contrary to what i wrote in the previous message.

New car makers have just about elinimated paper gaskets and now use silicone instead, except for the places where there is constant contact with gasoline..

Re: oops.. silicone and gasoline

peutoleum products though? because ATF isnt gasoline but COULD be peutroleum based if not synthetic.

anyway Im thiking of either retaping it or buying a new side cover...

Re: oops.. silicone and gasoline

like i said.. the car manufacturers are using silicone everywhere except with gasoline.

Just about everything is "petroleum" based.. from gasoline to motor oil to tar for filling potholes in the road.. Silicone will be fine in your application..

but don't let me discourage you from fixing that thing correctly :)

Retapping sounds like the best idea.

I invested in a cheap set of smaller metric taps/dies just a couple weeks ago. They are very handy even if you only use them to clean out threaded holes and straighten threads on bolts...

Yesterday i had a broken plastic throttle cable adjuster nut so i drilled and threaded a short piece of nylon rod to replace it.. took me 10 minutes and it works..

Re: oops.. silicone and gasoline

Go to discount or advance auto, and get one of their "universal" repair plugs for oil drains. It is similar to a boat plug, in that it is a rubber plug that is compressed by a nut to fit the hole, regardless of the thread condition. This will work fine, and will look a hell of a lot better than silicone.

Re: oops.. silicone and gasoline

I had a stripped oil drain plug on my Motobecane Sebring MO2 engine once. I was surprised to find an oversized 8mm threaded plug at Auto-Zone and it worked perfectly. don-ohio

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