4L80E Leaking

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Aug 6, 2018 | 01:11 AM

alextc

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4L80E Leaking

Hello,

I've got a 1983 El Camino that I swapped a 5.3L and 2002 4L80E transmission into. It has the stock, but shortened driveshaft and a 4L80E yoke.

I've had a leak at the outermost seal that you can see from underneath the car. I recently replaced the seal, but am still having the same leak.

I wiped it clean before taking the picture, but the ATF fluid appears to be coming from the black lip of the seal that contacts the yoke.

I've googled and came across many ideas around what this could be or how to fix it, but LS1Tech has been my most reliable source of information.

Any help would be appreciated!

Aug 6, 2018 | 06:33 AM

Jays_SSZ28

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Theres no end cap (welch plug) in that yoke. Whether thats the cause or not, that will be the next leak.
Is the bushing sloppy?

Aug 6, 2018 | 06:41 AM

forcd ind

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From: woodbine, md

Is it a new yoke? as said, bushing condition. Almost looks like the yoke has been sanded
on, not smooth. Some yokes used a pinhole in the plug in the back of the yoke to let air out,
but they used a seal to prevent oil loss.

Aug 6, 2018 | 10:53 AM

alextc

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So I purchased a new yoke and handed it off to the driveshaft shop when I had the driveshaft shortened. I can't say 100% that the new yoke was installed, but I'd like to think so.
I don't feel like there's much play in the bushing. I can check again to confirm though.

As far as the welch plug, is this the part I should be looking for?
https://www.ebay.com/itm/4L80E-TH400...-/261196700656

I might just install that before assuming anything else.

Aug 6, 2018 | 12:22 PM

Jays_SSZ28

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Quote:

Originally Posted by alextc

Thats not the part at all.

Your yoke should look like this, with or without the hole.
http://67-72chevytrucks.com/vboard/attachment.php?attachmentid=1143317&stc=1&d=137709 3070

If it has a sleeve inside like this below you can have a small hole in it (vented yoke) If theres no sleeve you need no hole.

I've never messed with a welch plug in a yoke other than plugging the hole when needed, just not something that comes up often.
http://www.geocities.ws/crosley_az/700speed.jpg

This is a welch plug https://www.sustainablesupply.com/to...aju2-c1316032/