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Discussion Starter · #1 ·
I was under my new EB Z last weekend snooping around and see a couple of drops of red fluid hanging off the front end of the tranny. I see that there is a small vent hole located at bottom of the bell housing that attaches to the front of the tranny, and this is where the oil is coming from. I also see a sticker on the LH side of the tranny near the fill port that reads "Use Dextron III ATF Only". Obviously, the red fluid I saw was ATF.

So I cleaned it off, hoping it was left over from manufacturing. Went out and drove the car for about 10 miles, and inspected for leakage -- none seen.

Then I drove the car to see my brother, which was about 120 miles round trip. Decided to take another look, and again saw the signs of leakage :eek: :eek: -- just frickin' great. Obvioulsy, there seems to be some leak problem here. Probably the input shaft seal, or worst case it could be a bad casting or some other bizzar problem. In any case, it's not something I wanted to discover.

So, has anyone else seen any ATF leakage out the small vent hole located at the front/bottom of the tranny? Maybe it's something that will "go away" (ya right) with some more miles?

Is the clutch located just in front of the tranny, or is it located at the rear of the engine. I guess I'm concerned about the clutch possibly getting comtaminated by the ATF if its located at the front of the tranny.

Anyone know if the tranny can be dropped without removing the whole rear subframe/differential etc?

Anyone have any ideas at this point besides letting the dealer tear the crap out of my car with 400 miles on it? :eek: :eek: -- NOT what I'm looking forward to!
 

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Leaks

ZeeOhSix

I Have no leaks at the bellhousing, There are known leaks on 01's at the halfshafts with a GM fix bullitton. Im gonna hope C4C5 will jump in and shed you some light..................

:-?
 

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Discussion Starter · #3 · (Edited)
Some More Details

I wanted to add that it never leaks when just sitting in the garage, but only when driving. Also, I could see evidence of ATF on the rear leaf spring area, just behind the tranny. This is apparently from droplets of ATF blowing off the front of the tranny when driving down the road.

It's not a very big leak, but after 100+ miles of hiway driving you can see that there where quite a few drops of ATF that had leaked and blown back -- and those are only the ones that happened to land on the leaf spring.

Also, I checked to make sure the tranny vent tube was not pinched. Found out that the vent tube is basically a hard plastic tube, so it really can't get pinched in any way. Also, there is NO sign of leakage of ATF at the main top vent tube.

I cleaned it up again last night, and will do some city driving only tonight to see if it appears again. Maybe it only happens on longer highway cruises where the tranny temp gets up some, and the speeds are higher? -- who knows. I think I want to analyze it some before I have to let the dealer looks at it.

IMA Z06 -- thanks for the input. Yes, if C4C5 could comment on this I would appreciate it :D.
 

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:( I am Bummed for/with you:( Hope mine is ok:-?
 

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ZeeOhSix,

I noticed some ATF near the rear of my trans when I first got the car. I wiped it off as best I could. I assumed it was from spillage during the fill at the factory. I'm going to put my car on the ramps tonight to check it again. I'll let you know what I find.

I also noticed one drop of gear lube on the rear end drain plug that I also thought was from the factory fill. I did not see any signs of drips from the seals, I will also check it again.

I have not noticed any drips on the garage floor.
 

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Discussion Starter · #6 · (Edited)
pmontelo

Mine has never dripped ATF on the garage floor, but you can see where it hangs from the front/bottom of the transmission -- just below the small "vent" in the bell housing to tranny interface.

Like I said earlier, I believe it only leaks while driving, and hence any leakage will drip on the road as your cruising, or it will blow back and land on the center section of the rear leaf spring.

I suggest eveyone take a peek at this area for signs of red ATF leakage -- mine may not be the only one :eek:.

More Info
I cleaned up the leakage and then went and drove the car for ~25 miles in just stop and go city driving. Got home and inspected the vent area on the bell housing again and did see ATF present -- she's definately a leaker :(
 

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Bone dry

ZeeOhSix,

I put the car up on the ramps and inspected the trans and rear end. Everything is bone dry, no ATF or gear lube present this time.

The place where I originally found the ATF was where the back end of the trans meets the body of the trans (about 4 inches forward from where it meets the rear end). My bellhousing has always been completely dry.

Weird thing, I inspected my bellhousing pretty closely and did not find the drain hole you mentioned. Where is it exactly and how big is it? I would have expected to find it at the lowest part of the center of the bellhousing, but there is no hole there.

One thing I did notice, where the trans is bolted to the bell housing, they really slopped on that black non-hardening sealant everywhere.

Hope you can get an answer from C4C5 on yours, maybe you should try sending him a private message.

Best of luck
 

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Discussion Starter · #8 · (Edited)
Vent Hole

pmontelo -- glad to hear yours is all dry. The vent hole I spoke of is located at the bottom of the bell hosing, where it attaches to the front of the tranny. The hole is small -- about 2x3 mm. Maybe yours is plugged up with sealant goop ?

I checked the fluid level in my tranny this weekend, and did find that it was slightly overfull, but only by about 5~6 ounces -- nothing significant. I took it out for a drive after draining the excess, and after 25 miles it still shows leakage. Like I said before, it's not alot, but it is wet at the vent hole at the bottom of the bell housing, and a few drops of ATF is hanging on the bottom of the tranny near this vent hole. There are no signs of ATF on the vent tube located off the top of the tranny. I think you would only see ATF at the top vent tube if it was drastically overfilled, and ran hard to make it puke.

I talked to the dealership about it and when I told them the Vette uses ATF in the tranny, the Service Advisor got this puzzled look on his face -- gave me real confidence. Now don't you think a dealership who sells 30+ Vettes a year would have a shop that knows that they use ATF in the tranny?

Anyway, this is pissing me off. It's definately taking away from the enjoyment one should have with a new $50+K car :roll:. If I could give the car back for a full refund at this point I would :flaming:. I cringe knowing that possibly the whole rear subframe/diff/suspension/ect may have to be dropped to get the tranny out. Just the thing that ever Z06 with 500 miles on it should have done :mad:!!
 

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Had a similar leak on my 2000.
Found out that the tranny was overfilled at the factory. Once we got the level to the appropriate point and checked all the screws...some were loose, the problem went away.

On the new 2002 I noticed that the exhaust tips didn't line up. Thought that I would have to do some bending. Looked at the metal tip that comes off each muffler and goes into a rubber piece on the rear of the car. There are 2 slots (one above the other) where the metal tongue goes. One side was in the top slot and the other side was in the botton one. Put them both in the same slot...bingo!!!
Must have done my car on a Friday afternoon:roll:
Bob
 

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Discussion Starter · #10 · (Edited)
Cape Cod Bob -- as I posted above, I did find a slight overfill condition on mine, but after dropping the level to the correct fill point (bottom of fill hole), it still showed signs of leakage :( -- not a good initial sign.

I understand that the whole diff/tranny/torque tube assy has to be dropped as a unit (after the whole exhaust system and whole rear subframe assy is removed) in order to get to the input shaft area. What a PIA! I would almost rather just let is seep and top it off once every so often than have half my damn car ripped apart !!

I think I'm going to put some more miles on it, and see what happens. Anyone interested in a 2002 Z with 500 miles on it?
 

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ZeeOhSix...We had a similar problem on our 99 Convertible 6 speed. Only it leaked a little more than yours seems to. Ours left a small puddle on the garage floor. Not just every once in a while, but continously it left about a half dollar size of fluid on the floor. When we took it in to have it looked at, I remember it being some sort of gasket, not sure what though. But I remember it was going to be a big deal. Meaning take the whole back end of the car apart pretty much. Drop the transmission. I know this doesnt shed any light on your problem, But that was our trans fluid problem. We traded the car about a month after this happend. The new buyer contacted us and we informed him of the problem. Hope he got it taken care of or else he has no trans fluid

Regards,

Andy
 
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Sorry but join the crowd, many owners have the same problem :(
My '99 leaks the same and seems it is either a porous trannie case or a bad case seal.
Being the fluid is light weight, it might be leaking even worse but it drys up quickly with the sumer temps.

The vent tube is at the top of the trannie and loves to puke after fluid heats up. I did an open road race in Texas and for over 70 nonstop miles I had a solid white plume of white smoke as fluid puked out vent onto both hot exhaust pipes.
A crap designed MN6 made in mexico. :(
G.M parts performance is not selling a trannie cooler for no reason and Z06s having a temp too hot idiot light.

John

ZeeOhSix said:
I was under my new EB Z last weekend snooping around and see a couple of drops of red fluid hanging off the front end of the tranny. I see that there is a small vent hole located at bottom of the bell housing that attaches to the front of the tranny, and this is where the oil is coming from. I also see a sticker on the LH side of the tranny near the fill port that reads "Use Dextron III ATF Only". Obviously, the red fluid I saw was ATF.
 

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Discussion Starter · #13 ·
teamzr1 -- thanks for the input. I know for a fact that there is no fluid coming out the vent tube at the top of the tranny. I pretty much guessed it would be a bad seal, or porous alumimum casting. The fact that hot ATF is very thin probably does not help the situation at all.

I'm going to check the tightness of all the bolts on the tranny as someone suggested, but my hopes aren't too high that will cure it. Mine is denfinately leaking from the front end of the tranny, so if it's loose bolts, it better be the ones that hold the bell housing to the tranny -- asssuming they go all the way into the tranny where it could leak past the threads. I bet its more likely a porous casting than a seal -- that's my gut feeling.

So what would you guys do? Leave it as is vs. having half the car ripped to shreads? Even though it's obviously a warranty repair, I just can't bear to have this done under a flat-rate "go as fast as you can" warranty job. If the clutch never could get oil contaminated, I might just let her ride as is -- haven't decided yet.
 
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I've tried torquing the bolts and was a waste of time. I agree with an ATF fluid case mating would be an issue with leaking and I find that when trannie gets hotter it leaks more then when its cold. Being the exhaust ad rear end dump heat onto trannie keep in mind under high RPMs for long periods that ATF foams and expands which increases vent puking.

I have zero interest in letting a dealer rip the whole ass end out so I just check the oil every time I put the car up on jackstands to swap street tires for race tires. I made it a bit better by adding a trannie cooler and thus I have much more total fluid so it can leak and not drop too low of a level as quickly

this winter I mite myself yank it out for the rear end seal also leaks like many C5s do :(

There have been reports of trannie and rear end leaking due to porous casting...

John


ZeeOhSix said:
teamzr1 -- thanks for the input. I know for a fact that there is no fluid coming out the vent tube at the top of the tranny. I pretty much guessed it would be a bad seal, or porous alumimum casting. The fact that hot ATF is very thin probably does not help the situation at all.

I'm going to check the tightness of all the bolts on the tranny as someone suggested, but my hopes aren't too high that will cure it. Mine is denfinately leaking from the front end of the tranny, so if it's loose bolts, it better be the ones that hold the bell housing to the tranny -- asssuming they go all the way into the tranny where it could leak past the threads. I bet its more likely a porous casting than a seal -- that's my gut feeling.

So what would you guys do? Leave it as is vs. having half the car ripped to shreads? Even though it's obviously a warranty repair, I just can't bear to have this done under a flat-rate "go as fast as you can" warranty job. If the clutch never could get oil contaminated, I might just let her ride as is -- haven't decided yet.
 

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ZeeOhSix,

I found the drain hole where you described it (on backmost edge of the bellhousing), I wasn't directly under it before, so I missed it. (picture attached)

Based on the fact that you said your leak is coming out of that drain hole, I would bet that they didn't do an adequate job of sealing the 1 inch wide flange (trans front cover) that bolts between the bellhousing and the trans body.

Looking at my trans, you can see black non-hardening sealant around the perimeter of the front cover and trans body mating surfaces, and in the bolt holes. I think there are at least 10 bolts that hold that front cover to the trans body. If they didn't cover the mating surfaces completely with sealant, ATF could leak through the bolt holes to the bellhousing area. You could also have a damaged input shaft seal, but I doubt it.

Based on how much sealant is slathered on my trans, I bet that is where the problem is.

Unfortunately if they need to drop the trans, the whole back end of the car has to come out. See:
http://64.225.48.150/chspeedfreaks/c5_t56break01.html

Given the small amount of leakage, I think I would live with it and check my fluid level as needed. The clutch is mounted on the flywheel on the back of the engine, so you shouldn't have a problem with contaminating the clutch surface w/ATF.
 

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sloppy sealant

Here is a picture of the sealant slopped on my trans.
 

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Discussion Starter · #17 ·
Holy Crap!

Pat -- thanks for the info and the link that shows what must be done to fix something like this. After seeing those pics, I think I'll definately just let it seep. Christ, the chances of something else getting fubared with all that rippage is way greater than alittle ATF leakage IMO. I can't bear to think about this being done on a warranty claim. You know the tech is going to go as fast as possible so he doesnt eat his efforts. Of course the tranny wouldn't have to be opened up, but I think your correct that its probably something on that plate that bolts to the front side of the tranny. Apparently, the factory was running low on RTV when they did mine :D. It's too bad that it torque tube can't be dropped with the tranny in place, and work done with the tranny in place.

I think I need a few of these ...:guiness: :guiness: :guiness:
 

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Discussion Starter · #18 · (Edited)
Some Insight

After looking at the pics on the linked websight, I see that checking the bolt tightness on the bell housing will do nothing for me. The bolts that hold the front face onto the tranny are behind and hidden by the bell housing. I see there is also another plug in that front face of the tranny (looks at about the same level as the fill plug on the side), plus the input shaft seal, and it looks like a seal for the shifter linkage. Plus, the fact that they could have missed some RTV in a spot, and the possibility of porous aluminum casting makes for many, many places where this thing could be seeping from :flaming:! Where ever mine is leaking from must be above the fluid level line because it only leaks when it's driven, never when it just sits in the garage.

Looks like the tranny in the pic below has some signs of on going leakage too. Look at the bottom edge of the bell housing ... hummm, I wonder if this is way more common than I think, and nobody crawls under thier car to see this carnage :roll:?

See the attached pic below.
 

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Some type of product fix ?

Anyone know if it is a input shaft seal leak if any auto trannie product that works with ATF would help reduce leaking through the seal ?

Just a thought ...

John
 

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Discussion Starter · #20 ·
John -- there are products to help make old, hard seals swell up and seal again for autmatic trannies (ATF additive). Don't know if this would help a new leaky seal or not -- my guess is probably not.

Too bad there wasn't a removable inspection plate on the bell housing mounted to the front of the tranny so you could peer in and see the front face plate of the tranny to help determine where it was leaking.
 
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