Trans drain plug torque

larrym

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Back again with another question, you folks are life savers! I installed a transmission drain plug on my 727, tightened the plug with the supplied O ring, and it leaked. Tighetened it s little more and split the rubber O ring.

My question is, how much torque is required to keep that plug in place so it doesn't vibrate loose? Would I be better off to find a nylon washer similar to the oil pan drain plug, wrap the threads with teflon tape, or...?

I have a new O ring on it now, a little thicker than the one supplied with the plug kit, and it doesn't appear to be leaking, but it's not very tight to me, but then I'm an overkill guy. :)

Thanks again...Larry
 

beanhead

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The factory called for only 150 inch-pounds on the pan bolts if that tells you anything, but I'd just snug it good against the o-ring, then watch it for leaks. You can always go a little tighter if it weeps but once it's overtightened, the o-ring will be shot and then no going back.
Personally and this is 'just me' but I prefer a delrin or copper washer for drain plugs...for rubber to work properly there needs to be a slight chamfer or groove in the pan bung to recieve the o-ring. If the surface under the o-ring is flat this may be the cause of your troubles...
 
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toolmanmike

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Back again with another question, you folks are life savers! I installed a transmission drain plug on my 727, tightened the plug with the supplied O ring, and it leaked. Tighetened it s little more and split the rubber O ring.

My question is, how much torque is required to keep that plug in place so it doesn't vibrate loose? Would I be better off to find a nylon washer similar to the oil pan drain plug, wrap the threads with teflon tape, or...?

I have a new O ring on it now, a little thicker than the one supplied with the plug kit, and it doesn't appear to be leaking, but it's not very tight to me, but then I'm an overkill guy. :)

Thanks again...Larry
O ring? A rubber O ring? That sounds like trouble.
 

larrym

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I agree beanhead, I'll look for a copper/crush gasket, not sure they make one that small, it's 3/8 ID, in the meantime I'll keep an eye on it and keep a couple rubber gaskets on hand.

Toolman is correct, rubber is trouble, I found that out already.
 

toolmanmike

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Here's a couple good designs. I like the metal one with the rubber center. You can't over tighten it.
1669158346424.png


drain plug gasket.jpg
 

toolmanmike

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Hmm, wonder if I can find one 3/8 ID, 1/2 or so OD. Stuff like that is hard to find near me (Alaska). What are those called technically?
Drain plug gasket. Any parts store should have one. A white nylon one will do better than a rubber o ring.
 
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