FMX leak through slip yoke?

Cougar Community Classic Cougar Maintenance Restoration and Repair
1

Hey group, your advices would be greatly appreciated here:
Since I got my cat few years back, there has always been a tiny leak of transmission fluid at/near drive shaft connection.
I changed the gasket last spring without success: still that tiny leak all summer long.
So I thoroughly cleaned the whole area when I stored the car last fall to observe what would happen at rest… Shortly after, few drops began to appear on the floor. Looked at it today and saw a drop of fluid, ready to fall, on the lower “ear” of slip yoke (see pic).
Gasket and yoke shaft are dry all around, as well as the upper “ear” of yoke… so it seems to leak through the yoke??? Is it possible? Any body has had similar problem?
Thanks in advance.

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FMX Tailshaft fix
2

Yes it can leak through the yoke, there is a plug (like a freeze plug) in the yoke where it attaches to the slip joint.

3

Right on. Mine had that same leak.

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4

Mine too. I changed the tailshaft twice before I figured it was that plug. That was over a year ago and I still haven’t fixed it.

5

Thank you so much guys, that is crystal clear!

6

I have the same leak. What did you do to seal the leaky plug problem?

Thanks

7

Removed the yoke, held it up vertically, dumped a bunch of black silicone down to the bottom, tamped it down with rod (broom stick might work), let dry for a few minutes, done. Reinstalled, hasn’t leaked in 10 years.
BTW, may want to rinse it out with varsol and dry before dumping in the silicone.

8

I would clean it really well with brake cleaner or some other solvent, then use an epoxy like JB Weld or similar to seal the leaky area. You can apply to the outside so you don’t foul up the splines.

9

Thanks to everone for the tips. I thought maybe you changed the pug.

10

You can do that, but it still has to be sealed.

11

Pulled the slip yoke out, nocked the plug out with a wooden dowel, used a ball ping hammer to put a dome in the plug just enough so you can snap it in place with your hand. cleaned everything up with brake fluid. Used RTV gasket maker around the edges, snaped it in place and flattened the dome out with a hammer. It has been over a week with no leak.

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