Which Is The Correct Or Better Rear Seal For The Dana 18 Transfer Case?

Sounds good. Thank you!

 

I read about sealing the spline on the output shaft and forgot to do it, after I put it all together and run it for a little while I got oil on my parking brake. I had to take it all apert and clean off all the oil and put sealant on the spline, it does not leak now, and the parking works great, just saying, Maury, Rick

 

I saw that sealing the splines was likely going to be a requirement. I plan to do that too when I tear into this. Thanks for pointing it out!

 

Late to the conversation, but better late then never!

Im the process of re-sealing my Dana 18 output shaft for the third time and this time Im replacing the companion flange and the felt seal with a new set from Kaiser Willys. I'm also considering the double seal solution like others are referring to. How did it work out? Did you just install one double lipped seal after the other? Do I pack the outer seal with grease? Do I still use the felt seal? Any help is appreciated.

 

"Did you just install one double lipped seal after the other?"

No, you can either install the standard single lipped seal, or the double lipped seal, but only one of either.

The double lipped seal is a good idea if you are using your old output yoke (companion flange). I always buy a new one because every one I have ever pulled had wear on the seal surface.

YES to using sealant on the splines. I also use the felt but it isn't really a seal, it helps keep dirt out of there which will destroy the seal.

 

Okay. That clarifies things. I purchased 2, double lipped seals because I was under the impression that some folks commented here that they are doubling up on those I.E. one on top of the other. Im looking for any improvement over the last two times I’ve replace this damn seal. So, I going with one, double lipped seal, a new companion flange and new felt seal. Fingers crossed that does the trick.

 

Did you also use the felt seal? Was there enough space for the final torque down? And did you apply grease inside of the outer seal for lubricant?
I apologize for the repeat questions. This is a somewhat confusing topic.

 

Outstanding. I will smack that second seal in behind the first tonight. Thanks!

 

The felt seal is simply a vestige of the days of leather seals. They were there to hold lube against the leather to keep it from drying out. I haven’t used them in at least 30 years. No modern manufacturer has used them in probably that long at least.
One thing you have to be careful about if you install 2 seals is to make sure the yoke dust shield/felt holder is to make sure they do not hit the seal. It will lock the transfer case output shaft up tight when tightening the yoke nut.

 

Excellent point. I’ll have to give some thought as to how i will be able to determine that depth given that you’re essentially torquing that down in the blind with the parking bake drum in the way.

 

Since these guys have done the double seals, they have more experience with that than I do, as I have not tried that. Didn't think there was room for it.

 

At first blush, it seems like it’s going to be a tight fit with the two stacked against each other. But at this point, I’ll try anything. I’m desperate. I’m so tired of taking this thing apart to stop this leak. And I know it’s coming from the seal because it’s leaking straight down onto my parking brake shoes. And yes, I’ve added the RTV onto the splines both times I’ve done this job.

 

They can be a real PIA to seal. One thing that is often not done properly is sealing the shims, but it doesn't sound like that is your problem.

 

As previously posted, you can use TWO stacked seals and these can be double lipped. That equals 4 sealing lips. The 15655 seals are thin enough to double stack them. I use wheel bearing grease to lube those as the outer seal should be running dry on the yoke/companion flange. That is the best sealing technique I have found and ran that better than 2 decades on my 3B with zero leaks. As also posted, if you are going to use the felt "seal" with the stacked seals, it needs to be trimmed to half thickness. That still works fine.

 

Update: I finally received the new companion flange from Kaiser Willys yesterday. Turns out it's a omix-ada Part #116714 and the shaft it approximately 1/4 longer than the stock one I had. I did think much of it until I tried to install it with 2, double lipped seals. I absolutely could not install the drive shaft back on even fully collapsed in! Im guessing that on the output shaft itself has some kind of shoulder preventing the shaft on the companion flange from inserting too far in? Or, the two seal I used combined were just too long so I couldn't install the flange deep enough? I pulled the emergency brake drum back off along with the new companion flange, pulled out the far outer double lip seal, ( leaving one in) and tried to reinstall. I was just barley able to re-install the drive shaft even after a full torque down of the nut. I used Permetex black silicone on the splines so I'm giving it a couple days to dry until I refill the Dana with 90 wt. I'll update later this weekend to see if the new flange combined with 1 double lipped seal did the trick.

 

Your mistake was buying anything from Kaiser-Willys. I know there have been previous problems with Omix's companion flanges that wouldn't even seat the e brake drum. DeBella sells companion flanges that are equal to the originals and I suspect there are several other vendors that have alternatives to Omix-ADA's absolute certified CRAP. IMO, that stuff isn't worth installing if it's free.

If your driveshaft is completely against the limit of its travel, this isn't going to end well.

 

Well, dammit. My fault for trusting Kaiser Willys on this. We’ll have to see if the leak reoccurs. Btw, I had to expand the rear drive shaft 1/4 to maybe 1/2 inch out from the rear axle to the companion flange after
The second seal was removed for final installation. I will say this, the new companion flange was extremely tight to press on compared to my old companion flange. I had to give it a few smacks with a rubber mallet just to get it started on the output shaft. I suspect the leak was coming through the splines on the previous companion flange.

 

Keep your old one. You may want to put a speedi-sleeve on it.