http://www.northerndrivetrain.com/product/SPI-500166-20.html

is this what you are looking for ??  you may have to do some more research to determine correct size/diam. look for dana/spicer parts
if so this may be useful   http://www.hubbardspring.com/install_reco.php?cid=45
stuey

It does help.  I got a reply on a Tbird forum I posted this question to also the guy posted a link that showed a picture of the yoke.  When plug was said I thought we were talking like a small 1/8" plug not a plug as in the whole back side of the yoke.  THe link which I will post below showed filling the plug in with a good layer of jb weld.  After seeing this I don't think I want to attempt to weld this up and I am sure the leak that just came up all of a sudden was due to drain back submerging the system which ironically the rear tail shaft seal was not leaking.  So I have to assume the tail shaft plug must have corroded through.

Now I am left with a delima as I can order a new drive shaft yoke for $80 but I have to check my transmission shop manual as I do not recall the output shaft spline count as the only one I have found is from Tee-Bird Inc and theirs is a 16 spline count but does not say application.

http://www.tee-bird.com/catalog_product_detailed.cfm?id=12107


Or I can try the fix shown below which is filling the plug in on the U-joint side with JB Weld.

http://www.ctci.org/gilsgarage/TransFluidLeak.php



1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi

Rusty,
Old Fordomatics, especially those with an air cooled ('built-up")  torque converter are very prone to "converter drain-back"; after May 1 1956 for most manufacturing locations in the USA,welded converters (which indicate water-cooled) transmissions were introduced; they have slightly lesser leakage issues and better alignment by design. This condition overfills the oil pan from the correct operation level by as much as 4 to 6 quarts, high enough so the rotating elements and planetary gears are actually submerged, as is the governor and even the output shaft. On a car driven daily, most do not notice this.  Even slight wear on the yoke and the bushing coupled with an old tail shaft seal can cause leakage, to a flood after many months sitting.  The most common cause of the drainback is wear, and misalignment; it was a common issue in the cast iron Fordamatics,  and Cruse-o-matics from 1951 up and all Ford products and others with the Borg-Warner designs.  Here in the States, a trade group (ATRA) published many fixes that helped, but data may be hard to find. All my old data went years ago when I sold my shop, but I remember some. The best of them was replacing the front pump bushing with one that had  a tighter tolerance, and using the newer style silicone based  front pump seal by TRW  was a help too. You can do the tailshaft seal and bushing replacement in the passenger cars most trucks without transmission removal; not so on early birds.  Alignment issues are hard for the average mechanic to measure and often even more complex to correct, especially when caused by casting creep/poor foundry practices.  
Hope this helps some
WLJ

Forget applying Che* locig to these fords ! remove the u joint and weld by brass weldng the plug in back of yolk.. Done !!!!!



  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

I found one at NAPA for a T-85 with OD. It's the same seal used in the FMX. I yanked what was left of my hair out for months trying to find one by asking for a seal for a T-85. Mostly got blank looks. So, if anyone else with a leaky T-85 reads this maybe I helped someone...

My seal is in great shape, thats why I have the pressure LOL. It's been running this way for about 5,000 miles with no problem so far. If I ever pull the drive shaft out in the future I think I'll add a small breather hole in the yoke.

No need, this post should help everyone, there is really not much information out there about this.

As far as yours the output shaft spline seal as I have seen it called by, I seen comments that ford used the same seal for all that had a internal slip yoke seal.  And they do all look the same but now the Cruise-O-Matic, C4, and FMX transmissions that use a inner slip yoke seal that I know of for sure I tried to find them and all I could find was out dated ebay listings of a box of NOS Cruise-O-Matic seals from years ago.

What you can try doing is one of two things.  You can try some local transmission shops that sell transmission parts and see if they have any of those seals they are willing to part with.  The other is modification, I read that thoses that use no slip yoke seal and has no hole in the slip yoke has two splines removed from the slip yoke itself so if allows the slip yoke to slide easily without binding on transmission fluid if some gets between the output shaft and the inside of the slip yoke.


1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi

I think that would be worth a try, not much to loose for trying. I apologize for getting your post off track..

Hmm if the plug is just simply nothing but a brass core plug or a steel core plug then hell instead of welding it up I might as well take the yoke apart knock the old plug out if its still there and use some sealer and drive a new plug in.  Be better than welding that's for sure.

1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi

Just for reference, this is the seal on the output shaft. The yoke has no splines in the first 1-2" that fits over the seal.