transmission drain plug

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Jakegday

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hello all. looking for some advice... how would one go about installing a drain plug on your transmission pan? is it possible to do "properly"??? or is there only the jerry rigged way that i can think of, and thats just sending a self tapping screw with a gasket/oring through the pan.

any input would be greatly appreciated, thanks!
 
You could remove the pan, drill a hole from the inside, weld a nut to the outside of the pan, and screw in a bolt that will go all the way through the nut for a good seal without sticking up too far in the pan. Preferably, there would be a magnet at the end of the bolt. Or just slash a hole in the pan with a chisel then plug it up with Mighty Putty and refill.
 
I have been using brass plumbing fittings that cost under $2 and give a very low profile so unlikely to be knocked off by anything on (or off) the road. Basically a brass plug that has a brass hex fitting that screws into it. You have to remove the pan and braze the fitting on. No leaks this way as its welded and the plug has a pipe thread. Bolts do not have a pipe thread, so not sure how you would seal them; telfon tape maybe.

I will try and get a pic as soon as I have a change.
 
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"Properly" depends on the tools at hand and the time
you're willing to spend on the project. I think the ultimate drain plug would be similar to what Rizzo suggested -- weld a nut on the pan and use a drain plug. I'm fortunate to have a couple dozen drain plugs my company threw out (one size only). I found matching nuts for them.

Always start with a drilled hole, placed at the rear of the pan where it won't interfere with the internals.

The best drain plug design I found was on my sister's Chrysler. It has a replacable o-ring under the head. You should start with that drain plug design and find a matching nut.

To take it down a notch, you can buy the drain plug kit and braze that to the pan.

Taken down more, you could buy the drain plug kit and simply install that. I wouldn't take it down to anything less.

Bluestream, I'm curious to see those parts.
 
Originally Posted By: Kestas

Taken down more, you could buy the drain plug kit and simply install that. I wouldn't take it down to anything less.



I've had one of the kits in a pan for... gosh... its nearly 20 years now that I think about it! No problems at all.
 
Originally Posted By: punisher
http://www.amazon.com/B-80250-Drain-Plug-Kit/dp/B00029WR78


I've used these type kits several times with no problems, except I replace the nylon washers with copper drain plug washer gaskets of the same size. I've seen the nylon washers crack from heat and age, and if they shrink, the nut may work loose and cause a leak. The copper washer isn't likely to change much over time. I also wrap the smaller drain plug with teflon tape for extra sealing.
 
The method I prefer it to get a short 3/8" bolt, a 3/8" nut, and a copper washer. Remove the pan. Locate an area with some clearance above it for the nut. Drill a 3/8 hole in the pan. Snug the nut and bolt in place with the nut inside the pan. Tack weld the nut to the inside of the pan. Remove the bolt and reinstall with the copper washer to seal it.
 
Originally Posted By: Kestas

To take it down a notch, you can buy the drain plug kit and braze that to the pan.



I did that - bought the B&M kit, thought it would be better to braze it on than to use the included nut and gasket. One problem - I left the plug in it when I brazed it on and didn't attempt to unscrew it until the next time I went to drain the ATF. The plug and bung are zinc plated, the brazing heat melted the zinc - so the plug is now permanently stuck
33.gif
Had to drop the pan to drain and got another ATF shower.
 
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I think that all these ideas are fine, except the oil in the pan will only drain to the top of the nut inside the pan. I would drill a small hole in the side of the nut before welding it to the pan and then even more trans fluid would drain out each change. Especially since less than half the fluid is exchanged each drain.
 
Originally Posted By: Kestas

Bluestream, I'm curious to see those parts.


Kestas, Here is what I have been using for drain plugs. Brass reducer fitting with a fine thread hex plug that threads in. These can be bought at any auto or plumbing place, and can be had in smaller or larger sizes. I weld in the bung, but I expect it could be soldered in as well. Has a lower profile than the B&M plug kit, and is 1/3 the price.

044.jpg
 
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Remove the pan and drill hole to fit large brass reducer, and screw it in. Then with a torch weld that in from the inside. (could solder it as well I guess) The smaller plug is a pipe thread and needs no teflon tape or pipe dope.

You can cut the larger fitting down, or grind it down after its welded in, if you want to get every last drop on a fluid change
 
Brass should work ok. Harbor Freight sells a copper washer assortment kit that is inexpensive-it probably has a size that will be close enough to work. I replace all my brake banjo bolt copper washers with these and they work fine.
 
I too vote for brass (or any other soft metal). This is considered a permanent installation. Elastomeric materials may take a set and leak in the future.
 
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