I tried doing a search but could not find an answer.

Today I noticed my transmission is leaking quite a bit of fluid with the engine running.  It is not coming out of the transmission itself but is actually coming out of the drive shaft yoke.  The rear transmission seal is dry as is the driveshaft yoke.  But on the back side of the yoke that faces the U-joint is wet and its dripping off one of the U-joint caps.

I know on certain scrubrolets they had a hole in the drive shaft yoke that they would leak from.  The fix we use at work is placing a solid steel spacer in to block the hole or welding the hole up.

I do not want to attempt this so this post is to ask how does one correct this issue?  It hasn't done it till now and the engine I got running again this past March/April.



~Update~

I did some reading and found out that the hole is for the slip yoke to slide without building pressure inside of the slip yoke.  I also found that on scrubrolets they have a Oring but my shop manual and even my parts and illustration guide shows no seal for this.

Now the question I am asking myself is I did jack the car up quite high by the frame to replace the front wheels as I took the spare off both sides (spare from my Mercury and spare from my '56) and installed the factory wheels back on with new radial tires I had installed today.  I am wondering if this caused this by shifting the fluid back resulting in the slip yoke being overwhelmed.  But then if that is the case what keeps the fluid from leaking out like this when you are going up hill.

I will be heading to bed as I post this as I cant wrap my head around this and I hope to hear something by tomorrow if not I will probably pull the driveshaft and cut a cork gasket material to fit the inside of the slip yoke and jam it up against the small hole to plug it.  Hate to do this if the purpose is to allow the slip yoke to slide without building internal pressure inside the slip yoke.



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

So i guess no one here knows how the slip yoke on a ford-o-matic seals.

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

It seals by the tail shaft seal only! If it's leaking from behind the yoke at the u-joints only real remedy is to replace the yoke... The plug thats at the end is factor welded or on some it is pressed in. I tried various ways and stuff to cure one of mine only to bite the bullet and get a new one! That solved my leak! Not what u wanted to hear but it is what it is. If you change the yoke I'd ck the play on the tail shaft bushing, if it's a bit sloppy it needs replacement then you will need a special puller to get it out and tap a new one in and of course new seal. Good luck.

Wait so these are not supposed to have a opening to relieve pressure in the yoke?  If not I can just weld the end of the slip yoke up.  I just didn't want to do that like we do at work because if it has a vent hole that is to allow the drive shaft to slide back and forth and I was afraid if I take and plug the hole up fluid would become trapped and hydrolock the drive shaft and not allow the slip yoke to slide.

I just want to make sure before I do anything as there are ways I can get around this even if that is pluging the hole I just could not find any mention of if it had a inner seal or not.

I know I found later on in the evening after my post above that the Cruise-O-Matics had what was called a output shaft spline seal which was also used on the FMX and the C4 transmissions but couldn't find anything on the Ford-O-Matic.

But thanks for the reply though it saved me a bunch of headache trying to figure this out if its supposed to be plugged.  I will probably check everthing as I want to install the dust shield and I might replace the U-joints if they feel bad but I can take and weld the hole up without disassembly easily.

Also if I just locate a new yoke for it and replace it would I have to get the whole drive shaft balanced again?  I never really replaced parts like this new that might potentially change the balance.


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

There  is a  Vent on the side of the Transmission to prevent internal pressure buildup.

  

True, I was talking more of pressure between the output shaft an the slip yoke.  That is what the vent hole was there for on some models that's why I didn't want to just weld it up till I was sure how this system seals as I don't want to cause more problems for me by fixing one problem incorrectly.

I did find out Tee-Bird products have a 16 spline slip yoke listed for the T-bird and the 55-56 fullsize cars for $80.  I am just wondering if I should say screw it buy a new slip yoke and front U-joint and just replace it over trying to weld it up.  I might have to sleep on it as replacing it I might have to rebalance the driveshaft and if not there will be that little bit at the back of my mind nagging me that I should or need to do it.

Just one of thoses things where I am very over protective of this car especially mechanically.

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

I'm glad you brought this subject up because I'm dealing with just the opposite problem. I have a later model T85 from a 61 Galaxie in my 57 and it has an output shaft spline seal. I had never seen one on any of the other manual trans I had worked on in the past. I'm using the yoke that was with the trans originally and it has no vent hole and you can feel the pressure when you install the drive shaft. Now I'm wondering if it should have one?

If you remove your yoke to weld up, or possibly it could be tapped and plugged, just mark the orientation so it goes back on the shaft the same way. I don't think a small change to the center will effect the balance.

Please take a moment and think about this. If the end of the yoke is sealed and you think there is too much pressure build up to move after greasing it, how would you ever get it to slide in in the first place? I looked at 3 yokes in my garage and they are all sealed with freeze plugs. Our 1/2 mile dirt cars drive shaft moves 3" in and out and I guarrentee its sealed. A stock drive shaft moves very little in normal driving (look at the seal mark left on the shaft). I'm sorry but, pressure on movement, I don't think so.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

If you have a spline seal it fits into the ID of the yoke. If the yoke isn't vented when you install the drive shaft you can feel the pressure and have to use force to get it in and when you let go it comes back out a little just like it was spring loaded..

When I had the tail housing off to replace the bushing I noticed this seal on the output shaft, first one I had ever seen. But like RUSTY said they were also used on C4 and Cruisomatics.

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.