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From my 94, engine and trans are coming out for a cam, clutch and some other maintenance.
This morning I pulled the exhaust and notice the tailshaft seal has been weeping. The driveshaft seems to have been flinging oil around.
I can wiggle the yolk up/down just a hair. I’m not sure if any play is acceptable here so cannot conclude if it is just a failed seal or if the tailshaft would be reconditioned.
I plan on reaching out to ZFdoc but wanted to see what the thought here is as well.
A few images and I’m going to try to upload a video as well but due to the awkwardness of one handedly taking video on my back while trying to demonstrate the play in the yolk it is shaky and I’m not sure you will be able to see what I describe above.
thanks,
jmgtp
edit: pics below, but was unable to upload video. CF maybe doesn’t like iPhone video format?
mine looks worse than that. You may also need the slip yoke machined if it has wear patterns to that.
also zfdoc gave me some advice that didnt work well in my situation.
he told me use a th400 bushing and use red loc tite between the seal and the housing (i usually would have put permatex or gasket sealer of some sort)
welp, i took his advice (with the red loc tite) and it leaks like a MF
Last edited by dizwiz24; Dec 21, 2019 at 01:27 PM.
Diz, other than the leak from the Loctite, did the th400 bushing work out? I’ve heard the seal is the same between the two but didn’t know the bushing interchanged. How are you certain the leak wasn’t from around the outside diameter of the seal? Any machining required on the th400 bushing to fit it or was it press out the old, press in the new?
edit - Nevermind my question about the origin of the leak. I re-read your post and see you do say it was from the outside diameter of seal.
I have a reconditioned ZF6 Tail shaft housing for sale if your interested. https://www.corvetteforum.com/forums...t-housing.html
The tail shaft was reconditioned by ZFDoc with new bushing and seal. Ready to bolt on and go.
Originally Posted by jmgtp
From my 94, engine and trans are coming out for a cam, clutch and some other maintenance.
This morning I pulled the exhaust and notice the tailshaft seal has been weeping. The driveshaft seems to have been flinging oil around.
I can wiggle the yolk up/down just a hair. I’m not sure if any play is acceptable here so cannot conclude if it is just a failed seal or if the tailshaft would be reconditioned.
I plan on reaching out to ZFdoc but wanted to see what the thought here is as well.
A few images and I’m going to try to upload a video as well but due to the awkwardness of one handedly taking video on my back while trying to demonstrate the play in the yolk it is shaky and I’m not sure you will be able to see what I describe above.
thanks,
jmgtp
edit: pics below, but was unable to upload video. CF maybe doesn’t like iPhone video format?
ZF6 is out and on the work bench. Interestingly I can get no play from the splined shaft with my bare hands. When I slip the driveshaft yoke back in, then I can get some wiggle, which I’m pretty sure is just a tiny bit of lash on the splines. Normal? Maybe this is just a seal issue? 116k on the clock. That said, take a look at the yoke, there is definitely some light grooving. I wouldn’t say I can “catch” it with a fingernail but I can detect it, if that makes sense. Also I think the u-joint is failing as it binds on one side, you can see if one of the pics the yoke is pointing up, held there by nothing more than the u joint. The other side of that same u joint moves freely as does the joint at the diff end of the shaft. These are about 10 years old, I’ll be replacing them with Spicers this time. I think these are Brute or something like that (I somehow had trouble finding Spicers at the time).
anyway, let me know your thoughts of the tailshaft housing, likelyhood of a seal only failure and the u joints as well.
I tossed in some bonus pics of the 12t stands that make clearing the zf a breeze, they’re not even at full height. This is possibly the heaviest manual trans I’ve worked with and lifting to the bench was risky on the old back for sure!
Also, does anyone happen to know for certain what size hex the release fork ball stud needs? I know it is not a size in my current inventory. I measured 12mm with a cheap caliper, but hoping someone can confirm before I buy one.
It's been quite a few years since I had mine all torn apart, so my memory has faded a bit. I got good advice and help from Bill Boudreau (ZF Doc), and can definitely recommend him. He hooked me up with a fresh tailshaft bushing which was a bit longer than the OEM piece. He also found an NOS driveshaft yoke for me. They are hard to find now, but Bill can cut down a yoke that's for a different application to shorten it so that it will work with the ZF in a C4.
I don't recall the size of the hex for the fork ball, but you should be able to trust your caliper. IIRC, something's reverse-threaded in there, so check on this before you crank too hard on it. Bill can advise about all of these things, and more.
ZF tailshaft bushing question
