** Update, new seal leaks? FJ45 differential seal question **see pictures

[Wadesters]

Replacing rear diff seal. Part number shows 90311-38028 in my parts book. I have one of those seals but it looks different from what is on mine. First picture is before I remove. 2nd picture is of the part I have. Can anyone tell me if this is correct part? I thought it was leaking but looking inside it looks dry. Just thought it would be a good idea to change. Might have been changed before and maybe correct one is was not used. Thanks..

 

[Wadesters]

@JackA thought seal has been updated to what I have. Just seeing if that is everyone else’s experience.

Is the best way to get old seal out to drill 2 small Phillips head screws in it and pull out? I have a cheap seal puller not sure it will get it.

 

[JackA]

I have a cheap seal puller and it works just fine.

 

[71-CRUISER]

Just an updated version of the pinion seal.

 

[Wadesters]

Thank you…

 

[Wadesters]

Pinion seal replaced with new updated seal. Seal is leaking.... Any ideas? I made sure to get the seal in straight on all sides and all the way in place. Another thing I thought was strange was the pinion nut had a cotter pin in it. When I removed the cotter pin the nut was not very tight. Although for cotter pin to be in correctly it could not be a whole lot tighter.

Bigger issue is with new seal leaking

 

[Wadesters]

The seal I took out is: NOK TB387411X3

 

[locklaw]

Where did it leak? Seems not the side of the seal so either on the sleeve part which may be grooved or through the splines. The splines are very oily on the photo. Did you put sealer on the splines?

Also, if the pinion nut is not torqued to spec the pinion will move "in and out" ever so slightly. It will also allow some up and down movement. Not good for sealing it up.

Rather forego originality behind a flange where you can't see it and go with the updated staked nut type to get the pre-load spec correct.

 

[Living in the Past]

How's the surface on the flange look where the seal rides? Did you test fit the seal to the flange before installing?

If the nut was loose to start with and cotter pin keeping it in place probably indicates pinion bearing wear.

 

[Wadesters]

Thanks! It is leaking from lower part of splines onto rubber of pinion seal. I did not use sealer on splines. Pinion has not moved in or out as frame is sitting on gojacks.

Staked nut would be good as I had to also use a different seal than came out of it.

Seal that came out was an NOK TB387411X3

This truck sat most of its life. Not saying it could not be worn but don't think it has very many miles.

 

[locklaw]

Thanks! It is leaking from lower part of splines onto rubber of pinion seal. I did not use sealer on splines. Pinion has not moved in or out as frame is sitting on gojacks.

Staked nut would be good as I had to also use a different seal than came out of it.

Seal that came out was an NOK TB387411X3

This truck sat most of its life. Not saying it could not be worn but don't think it has very many miles.

Ok. I like Indian Head/Loctite shellac for this purpose, but a good RTV like Right Stuff on the splines will also help.

While it did not drive now, I suspect it will some day so might as well do it right and get the pre-load correct

 

[Wadesters]

Thanks! Yes doing a full restoration. I will have to research about Indian Head/Loctite shellac on the splines.

Also unfamiliar with pre-load so will see what I can find in reference to it.

 

[Wadesters]

If I read correctly I am supposed to use rtv on splines before I re-install coupler, nut, and cotter pin?

I think the newly installed pinion seal is holding. Seems to be leaking above seal and below splines.

 

[locklaw]

If I read correctly I am supposed to use rtv on splines before I re-install coupler, nut, and cotter pin?

I think the newly installed pinion seal is holding. Seems to be leaking above seal and below splines.

Yes. RTV first, then the flange, washer nut and cotter pin. You want to assemble everything with the RTV still wet and pliable, otherwise you will push chunks of RTV into the pinion bearings

 

[Wadesters]

Thank you. I am traveling for 2 weeks but will try this method on my return. I assume I need to clean the spline area with brake cleaner etc… so rev will adhere..

 

[Malleus]

I'm completely confused by the RTV advice. The pinion seal rides on the smooth journal behind the splines. How would applying RTV to the splines seal the differential? Exactly where in the FSM does this step occur?

FWIW, I used to be the process line engineer for the heavy duty drive and drive-steer axles for Dana. There is no way any axle on my line was ever built this way.

If you seal is the correct seal, and it's leaking, one of two things has happened. As @Living in the Past said, the journal surface the seal contacts must be clean, unmarked ( smooth) and it must he the correct diameter (you can look this up in the seal manual), otherwise the seal won't seal. Second, you may have rolled the seal lip when you installed the shaft.

 

[pb4ugo]

I use permatex #2B non hardening sealant in this application. I believe Toyota offers a similar product. Or you could use Aviation sealer, but its a pita for future cleanup. There is slight movement between the pinion splines and the pinion flange. Regular rtv dries hard so at some point the hard sealing rtv breaks apart from the splines because of this slight movement and allows gear lube to pass thru. Non hardening doesnt do that. The nut and washer needs non hardening sealant too.

 

[Living in the Past]

Thanks! It is leaking from lower part of splines onto rubber of pinion seal. I did not use sealer on splines. Pinion has not moved in or out as frame is sitting on gojacks.

Not sure what you mean lower part of the splines. If oil is coming past the splines it will be leaking at the pinion nut. If it coming out behind the dust shield it's leaking between oil seal and surface on the flange. You say it has low miles but if sat for a long time still possible has surface rust even in AZ. I have transmissions stored in a garage. I keep oil in the and spin the input shaft with the transmission in gear just to keep oil on the gears. Still haven't seen a picture of the surface on the flange. The nut being loose when you removed the cotter pin meant something wasn't right. Preload doesn't go away from lack of use.

 

[locklaw]

I'm completely confused by the RTV advice. The pinion seal rides on the smooth journal behind the splines. How would applying RTV to the splines seal the differential? Exactly where in the FSM does this step occur?

FWIW, I used to be the process line engineer for the heavy duty drive and drive-steer axles for Dana. There is no way any axle on my line was ever built this way.

If you seal is the correct seal, and it's leaking, one of two things has happened. As @Living in the Past said, the journal surface the seal contacts must be clean, unmarked ( smooth) and it must he the correct diameter (you can look this up in the seal manual), otherwise the seal won't seal. Second, you may have rolled the seal lip when you installed the shaft.

The sealant is used not on the journal surface. That is what the seal is for and if the surface is grooved or the lip is rolled, it will leak as you rightfully state.

In your years at Dana you did not assemble and QC 40/50/60 year old worn components. You did it on newly machined components with tight tolerances.

The tolerance between the splines of the pinion and the inner spline surface of the flange wear over time, leading to enough of a tolerance forming that oil can leak through. Hence the suggestion to use a sealer to seal the tolerance and prevent this from happening.

 

[Malleus]

Splines are not oil seals. Even when new.