Dana 44 Pinion Seal Issues

Ok, I am stumped. I have tried several seals available for the rear pinion, and NONE will work without interference. When bolting in the yoke, the spline fit is snug, but the yoke appears to go into the diff case too far, and interfere with whatever seal I use. No change to pinion shims, simply replacing a leaky seal.
I have used a flat seal from Walcks, and the Omix-ADA seal, both will not work without interference.
When I removed the old seal it was leaky, but otherwise fit just fine. I did not save it as I did not expect any issues with a seal....
Tried both a new yoke and the original yoke. WTF do I do now?? Has anyone ever run into this?

 

I tried it both ways, I was told the " spring" side faces toward the yoke. Seal installed other way interferes with the seal itself & binds. Looks like I need a seal that is recessed.

 

The lip (spring side) faces in, toward the oil pool. The first picture is backwards. The third picture looks perfect.

There is the yoke, a dust shield, the seal, an oil slinger, and the bearing. If you have all those pieces in place, and you can't tighten the yoke without smashing the seal, something is wrong with the bearing or pinion shaft.

Looks like you have a yoke with no dust shield. Is it the same depth as the other yoke? Did you try assembling the pinion without the seal?

 

That may be, but the seal is then proud of the end of the diff and interferes with the yoke. There must be a different seal needed?

 

Another comment - once the seal goes in, it's either in for good or it's trash. You cannot expect to reuse a seal that has been installed and removed.

This is a very common part - lots of Dana axles use it, and there are millions of Dana axles on the road - your local parts store may have it in stock. You don't need to go to a Jeep specialist to buy it. Jeep PN 998092; SKF 15788 or Timken 5778 or National 5778. More Information for SKF 15788

Assuming you got the right part, it's not the fault of the seal. The Omix 1652101 points specifically to PN 998092. If the lip of the seal is seated in the housing, almost certainly there's something else that's missing or broken.

Note that a problem with the outer pinion bearing will make the seal leak.

 

The dust shield is in place, there only a small amount of gear lash, and no play on the pinion shaft end-wise. Both the new & original yoke have the same extension, {about 0.9"). The rotation of the gears feels smooth with no issues.
As all I have done is remove the old yoke & seal, and attempt to replace, hard pressed to imagine what could have changed. The yoke will slide on the splines until the pinion shaft hits the washer. So is there a dimension the pinion shaft should extend past the housing?
I have a rebuilding manual, but little info on the specifics of the pinion seal for rear axles. If the pinion is only pressed in on a bearing, is is possible that it could be pushed into the axle, and if so would this cause obvious issues?
And, yes I have gone through a number of seals at this point.

 

Is there a crush washer on these things?

 

I'm at a loss for whatever else could be wrong. If you look at the picture of the SKF seal, you will see a red ring that is a sealant between the housing and the seal. (If your seal does not have that, you should apply a little gasket sealer to seal between the housing and the seal.) That edge has to go all the way in to the housing - make sure the seal is fully seated. With the SKF seal, all of it is recessed below the level of the housing.

There are shims between the inner pinion bearing and the housing that change how much the pinion shaft sticks out of the housing. These shims determine the mesh pattern between the pinion and ring gear, but the change is small, measured in thousandths of inches. The outer bearing and race goes in, there is an oil slinger that's maybe 0.01" thick, and then the yoke and nut pulls it all together. You could add a small spacer on the end of the pinion shaft, under the seal, and this would put the yoke a little further out of the housing. Should not matter as long as there are two full threads showing beyond the nut, and the seal is riding on the sealing surface of the yoke.

 

Meant to say oil slinger is in place. The dust shield on the old yoke is not compatible with the new yoke.

Not that I see. The splines mate and the end of the pinion eventually hits the washer under the nut. That determines depth.

I also happen to have another older Dana 44, 51" wide from a late 60's CJ, but has 3.73 gearing. I removed the yoke to get the seal #, and measure the projection of the pinion w/ respect to the diff housing. Exactlly the same as my 'problem' child, 1.55". The seal is National #14823, NLA. It looks very similar to Walcks flat seal with an added depressed ridge around the seal such that NO part of the seal is proud of the end of the diff.
I assert the correct seal for this axle is NLA. I may be able to use Walcks flat seal, but it rubs significantly against the yoke. Not sure what will happen over time. There must be someone out there whom has seen this??

 

I may try a spacer at the end of the yoke. Still should hit the end and seat, and then I can use the replacement seal.

 

Not according to my parts book. The 20 has one IIRC, but not the 44. The 44 diagram shows shims for both the inner bearing and the pinion, part of kit 649228. But all of these are shown on the inner side of the pinion - shims on the outer side would do nothing but change the yoke seating depth, not affecting the gear mesh.

I would not assume anything about the axle - it's a D44, and there are millions of them out there. Perhaps you can call Walck's tomorrow? Or maybe order that SKF seal?

 

Nope spacer won't work. Interesting writeup on this very issue... no resolution, other than the seal Walcks sells.
Axle Rebuild - Pinion Seal Problem
The seal is independent of the bearing preload. It does appear a completely flat seal is what is needed.

 

Removing the seal destroys it. I've used up several.

 

Just today I replaced my rear pinion seal. I used the National 5778V without issue.

 

It's in backwards.

 

Your 3rd picture is correctly installed and is below flush with the housing, what is the yoke hitting? You say it "interferes with the yoke" do you mean it hits the rubber that is sticking out? This is a dirt seal and can contact the yoke.

 

Yep. the yoke hits the seal rubber projecting off the metal. The flat seal I used from Walcks projects the least but still causes the yoke to bind- almost cannot turn by hand. The other seals simply deformed and the pinion would not turn at all, no matter what way it was installed.
Anyone confirm the dimension between the end of the yoke and the diff housing?
Turns out the CJ2a guys have run into this quite a bit...

 

Here's the profile of the National seal (second picture) - More Information for NATIONAL 5778

I'd think you could put a new blade in your Xacto knife and cut off the lip, if that's the problem.