D18 Rear Shaft Leak - Follow-up

This is a follow-up to a previous thread posted by another member.
Previous Thread

I have heard numerous threads about D18 leaks. As many others mine is leaking out of the rear shaft. The tcase has new bearings and seals.

The felt on the rear splines is completely soaked and it makes a mess of the parking brake. Since the felt is soaked it may not all be coming through the splines but actually past the inner seal.

Are there any other options besides LOTS of RTV? Is it possible to get an O-Ring or other type of seal over the shaft?

As always, thanks for the input.

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Leaky D18 = :dead horse:

 

RTV on the splines, RTV around the outside of the seal. If the seal bore is scored at all it will leak between the seal and housing. I put the seal on the inside of the yoke before installation on the transfer case side. That way when the yoke is installed it "smears" the sealer down the splines creating a better seal. Make sure the seal surface is in excellent shape on the yoke as well. ANY pitting and it can cause a leak. Make sure you lube the lip of the seal before installing the yoke or it can cut or damage the seal. Make sure the garter spring hasn't popped off the back side of the seal. I put some assembly lube on the back side to help keep it from popping off during seal installation.

 

Thanks for the reply. The shaft and yoke were replaced when I rebuilt the tcase. I put RTV on the splines and on the outside of the seal when I first installed it.... Maybe I was not generous enough around the splines

I don't recall a spring being on the back side of the seal when I bought it and installed it. hmm, I wonder if I should order a new one before I go through the trouble of putting it all back together, again.

 

Some seals use a garter spring and some don't. I've found the ones that don't are more likely to leak. I think I forgot to mention I don't use the felt.

 

I made several calls and only one local place has the National Oil Seal #473229 in stock.

So I am going replace the seal and use excessive amounts of RTV.

You mentioned that you don't use the felt. Does it matter if the felt is there in addittion to a newer style rubber seal?

 

Imo the felt is a leftover from the days of leather seals. Imo the felt also holds any debris against the seal once it gets in there. Plus it makes it very difficult to set endplay properly as it puts pressure between the yoke and seal. I haven't used the felt for at least 15 years with very few leaks.

 

Yup. Me too
Posted via Mobile Device

 

Thanks for the advice all!

I got the seal replaced this weekend and it works great, so far.

BUT, leaks have now appeared in other places (speedo cable) that weren't there before.

Never ending battle!

Federal Mogul 473229.

 

What's the best way to drive the seals in place? Since these are sunk down in, you can't just rely on the 2x4 and hammer method. I tried gently tapping mine in place with a drift but I damaged them in the process.

Thanks.

 

The seals bend very easily.... I have seen people use PVC pipe that is the same diameter as the seal. I had a large enough socket to drive it.

 

Ah PVC! That should work perfectly. I had some sockets the right diameter but were not deep enough to clear the shaft. I was looking around the garage for ideas, PVC didn't occur to me.

Thanks.

 

For driving in seals and what not I keep old bearing races. They work well.
If you have an extra 18 transfer case front output clutch laying around (we all have one of those right?) they work perfect. A deep socket of the right diameter, pvc or metal tubing, etc.

 

I wanted to provide an update after running it for a few weeks.

The double lipped seal (Federal Mogul 473229) was the answer. The seal that I had in there before must have been junk; it came in a "kit".

Lesson learned for others? Be sure to get a better seal than what comes in the kits.

 

Just to follow-up from the previous thread. Mine has not leaked a drop in about a month. I replaced the speedo driven gear and paid meticulous attention to fluid levels and the leak around the speedometer cable seems have have been fixed.