Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

changing output seal on zf hsw 450d Direct drive transmission

Recommended Posts

So I've been trying to track down the source of my transmission leak on my 01 SS Lxi.  I had a thread going before the crash.  Anyways, I have checked the coolant lines and fittings, all is good.  I was looking at my transmission more closely tonight and the black factory paint is all bubbled up on the face of the seal around the output, leading me to think that this is where my leak is.  I also think the stern motor mounts (on the transmission) are looking tired and this may have resulted in the rear of the motor dropping and putting pressure on the output shaft.   I need to dig in further, as I have not yet separated the coupling on the shaft to see how alignment is.

My question is:  how tough is it to replace the output seal on this trans?  I have read that a special socket is needed?  Is this right, or can I buy a new nut and not need the special socket?  Anyone done this and have any tips?


Link to post

I meant to include this pic to show how far I've torn it down.  I'm eIMG_1181.jpg.e005efbbd08d2b5cfbd79109a733a61c.jpgven thinking of pulling the transmission off and replacing the input seal too since I've gone this far...

Link to post

I'd be inclined to change the bearing also if the seal is bad.  Heck, maybe the damper plate too if you end up pulling the transmission. 

I don't know what socket is needed, but it can't be *that* special, can it? 

Link to post

From what I have seen, the nut, instead of the usual hex, has four slots around the face, sort of like a Ford 4x4 hub nut.  I think I'll either make the socket or drive the nut off with a punch as I have heard of others doing, and replacing the nut.  Good call on the bearing; I have not learned how hard that bearing will be to replace yet. 

There is so little shaft exposed on this boat I cant slide the hose connecting the packing nut forward enough to see how the shaft is aligned in the log.  How hard is it going to be to remove the coupling from the shaft?  I think I'll have to get it off in order to get a puller on the output flange of the transmission.  Then I might as well replace the cutlass bearings....

Link to post
2 hours ago, hmh800 said:

Then I might as well replace the cutlass bearings....

Heh heh heh.  When will it end?

Link to post

OK, so I disconnected the drive coupler and the alignment is good.  I feel like I'm looking for issues that aren't there!  Although now would be the time to address them.  Cutlass bushings also seem good- there is no play in the shaft.  I had thought that the upper bushings on my transmission mounts had collapsed possibly leading to misalignment on the coupler.  But in looking more closely they don't seem so bad.  See photo.  The boat, although it is a 2001, only has 350 hours on it, and it's very clean.

But the bottom of the transmission is definitely wet with transmission fluid...which is what started this whole thing, a leak that I can't trace.  From the pics you can see that the paint on the seal surface is bubbled, as are a couple of areas on the bottom of the case.  I think what I need to do is to pull the transmission and replace the input and output seals.  Seems odd though that the paint on the output flange is going away.  I had thought it was maybe from heat because the bearing was being side-loaded, but now I think it's probably from the seal leaking and saturating the paint.

Thanks Gary and everyone else for your input.  I'll be sure to post up what I find hopefully it will help somebody else.


Link to post

Everything looks clean, so maybe it won't be too hard to remove parts.  I can't figure out what kind of crud or inverted seal material is sticking out along the output shaft in this photo:


It sure looks like part of the seal lip, but maybe it is just some goop that spooged out when they installed the seal.  Or maybe the seal has a long skirt on it, and part of it is missing?

Link to post
2 hours ago, wdr said:

Or a previous owner tried to fix the leak with a silicone based sealant.

That is the most likely cause....  :Doh:

Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...