Z06 Tranny leak or not?!? help?

[rocket71]

A little background info, my '04 Z06 has 6100 miles. It has spent the last 10 years trailered all over to AutoX's. When I bought it about 18 months ago I noted when tying it down to the trailer that the right rear side was covered in fluid/dirt caking. Over the winter I cleaned it off and noted a drip what I thought was between the torque tube and transmission input. I didn't have time to try to get it fixed before the season started. Well, the winter is here and finally got the transmission and stuff out. Not sure where the leak is coming from. Here are a bunch of photos....

LOL. The car as she sits...




Here are bunch of pics of the left side no fluid coverage compared to the right side. Then I am posting pics of the input to tranny, output, etc for reference because I can't see any evidence of leakage. I think it is the overflow tube but man that is alot of fluid.

Right side, gas tank cover. It is the most nasty.



Left side...



Torque Tube output....



Tranny input






Transmission



Vent tube shot



transmission output



Diff pic...it is covered.




As clean as the vent tube area is I am not sure it is leaking from there either now. Any thoughts?

Also, while I have all this out, is there any recommendations on anything I should take care of while in there?

I plan on putting a remote clutch slave bleeder in but from that I am just not sure. Axle seals? Torque Tube bearings?

Thanks in advance for any help.

[lcoleman]

The area in front of the vent tube seems clean, but the area immediately behind it is covered in gunk. I'd say that pretty much confirms it's the source of (at least one of) your leak(s). Especially with the vent side being slimier/dirtier than the other....unless I'm mixed up on how the transmission is oriented in the car?

[rocket71]

That's pretty much how I see it. There is some forward of vent the tube. The car at times would a spot on the ground and you could see a fresh drip from what looked like between the torque tube and transmission. I think that was getting slung up later.

[lcoleman]

How much fluid are you actually losing? Was the level noticeably low? Honestly, I'm not sure I'd even worry about it given how the car gets used.

[MikeKelly]

Observations from a long time autocrosser / dirt tracker / car guy / who's actually had a T56 completely disassembled (+ put it back together).

1- That is really a lot of grime for 6100 miles.

2- I think, judging from the top / front of the torque tube input image, that you have a valve cover or intake manifold leak (oil).

3- By the looks of the T56 input area, I don't think you have much of a problem there.

4- There's something missing off the end of your T56 vent tube. But I'm not at all certain that's the only leak in that area. Especially off toward the driver side, but that could be working its way back from valve cover / intake?

5- If that's actually transmission fluid pictured below / forward of the vent (red fluid) - that is definitely from the vent tube / missing baffle or vent (whatever the "proper" name of that missing piece).

6- I don't see much sign of a leak at the output of the transmission, but the discoloration of the output area really, really bothers me. That area, I don't think, should be that color. It screams "overheated" to me. But I can't imagine the seal would look that good if that area had been "that hot". Not sure what to think about that.

7- See #6 regarding coloration of differential input area, except I can't see a seal to tell how that looks. All that discoloration in that area (6 + 7) might be a differential front seal leak???

8- Again, that's a whole lot of grime on the bottom (?) of the differential, for 6100 miles...


There's my analysis, front to back, hope it helps.


Mike

[MikeKelly]

6- I don't see much sign of a leak at the output of the transmission, but the discoloration of the output area really, really bothers me. That area, I don't think, should be that color. It screams "overheated" to me. But I can't imagine the seal would look that good if that area had been "that hot". Not sure what to think about that.

7- See #6 regarding coloration of differential input area, except I can't see a seal to tell how that looks. All that discoloration in that area (6 + 7) might be a differential front seal leak???

This morning I see that the differential is actually open to the rear of the transmission, and the seal at the back of the transmission has transmission fluid on one side and gear oil on the other.

So the coloration is no longer a concern.


Sorry, never had a Corvette like yours apart...

[MikeKelly]

See the picture below for what the end of the vent tube should look like.

In conclusion, I think if you find (and eliminate) an oil leak somewhere around the top rear of the engine, and get the proper vent / cap on your vent tube, you'll have a whole lot less grime down there.


Mike

[rocket71]

yeah, the car only has 6100 miles. I know the two prior owners well and don't think it is any higher than that. I did get ahold of David Lehman the original owner and he said that since he bought the car new it always would drip a bit of tranny fluid when on the trailer. He said, he would just check it once in a while and add if needed. (please note, this car was notorious for the poor appearance it had during his ownership and before Robert got it. David admitted he never even washed it once during his ownership.) So I guess it has 10 years of a constant tranny drip.

I know it isn't a engine leak because there are none to be seen. The only thing weird is how far foward of the vent tube the leak was flung.

Yeah, I see my tube is either broken off or not made properly. I am wondering if I couldn't mount a small catch can somewhere to prevent this type of leakage? Now I need to find a good way to get all these parts clean before I put them back in.

[jcox07]

RC had a problem with oil starving once and I think had to remove intake. If he did remove intake and or heads to fix it, could be leaking out of the back where you can't see it. Just a thought.

[MikeKelly]

Any small catch can will be fine for the T56 vent - it won't take much - as in - any small remote MC reservoir would be plenty.

Regarding the back of the engine / top of the bellhousing (or whatever you want to call that area with a torque tube) - depending on how "wet" that is - that could have been there for years (and previously repaired, but not cleaned).

But do watch for some sort of a "pressurized blowby / crankcase pressure leak" - it doesn't take much of that to overcome PCV circuits that are only designed for "perfect" engines.

Maybe consider a catch can off the valve covers...

[dewittpayne]

The only thing weird is how far forward of the vent tube the leak was flung.

Air under the car doesn't always flow the way you think it should. There's likely a lot of turbulence which can make what looks like strange flow behavior if you are only thinking in the laminar flow regime.

[dewittpayne]

I've thought of a possible test to determine if the oily gunk has an engine oil or transmission fluid origin. Put some of the gunk on a paper towel. If it's transmission fluid, you should see a red stain developing around the gunk. If it's engine oil, it won't be red. It's pretty obvious that the gunk around the vent tube is from transmission fluid as it's red in the picture. The right side gas tank cover gunk, OTOH, looks like motor oil to me.

[rocket71]

Jeff - I sent Robert a note asking about the oil starvation thing you mentioned. I know it had the normal oil in the intake issues from needing a catch can and he said he had wanted to do that. I put one on and you would not believe the oil that gets put into the can. I think that might be what you are referring to.

MikeKelly - yeah, as I mentioned about, I got a catch can on it now. The intake used to almost leak oil it got so much blow-by in the intake. I think that is where some of the power was found during the dyno tune. I need to do some seafoam to clean out the residue.

Dewitt - yeah, all the fresh leakage was red tinted. What you see in some of the photos, ie..the one of the right side gas tank cover is from the diff fluid, had to use it really quick as a diff fluid drain pan when the diff turned sideways and started spilling out the axle seal.

I check again...no leak from the motor.

[MikeKelly]

Now I need to find a good way to get all these parts clean before I put them back in.

Pressure washer + simple green works about as well as anything.

[jcox07]

Yep, Berry that was it , when u talked about catch can that jogged my brain and it was a catch can due to oil in intake.