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My C7 Z51 is almost totally track dedicated, other than driving to and from the track. I've noticed for several years now oil on the floor towards the rear of the car.
A Chevy dealer told me that fluid is venting from the tranny, and an independent shop has told me that fluid is venting from tranny and diff vents. (Car has a transaxle but two separate reservoirs.)
The independent shop has just told me that I should install catch cans on both vents. The shop owner told me he had to do the same thing to a Mustang that hits the track a lot.
yeah a few quarters and up to a dollar bill sized splash when I park in hot days
You just going to live with it? It bugs me. When I come home from the track about the same size puddle you describe is on the garage floor the next day.
Think I might go the catch can route. Empty the catch cans and check trans fluid level every other oil change or so. Found a specialty Corvette shop near me that can install it/them.
I have the same issue, too, like many others. I never top it back, though, thinking maybe when its level is low enough, it will stop leaking, since it leaked a lot less with its original fill (which I think was below the fill line). Do you guys top it off every once in a while?
Anyway, a catch can would be great. It messes up the whole rear subframe, and could even be a fire hazard one day. It didn't look like one could add a catch can without significantly lowering the transmission for access, though.
Note, I don't think my diff leaks, but both my C7 Z51 (after first fluid replacement) and C7 Z06 leak transmission fluid. On the C7 Z51, I even had the dealer dye the fluid and trace it back to the top breather..
I noticed the same thing while I was at COTA last weekend. Had a tech from LG Motorsports (they were on site tuning a C8) take a look at it and he told me it was normal venting as you guys described. However, after sitting idle in the garage for a couple of days, I noticed more fluid leaks (fortunately, I put cardboard under the car to avoid a mess in my garage). I took the car to the dealer Thursday and I'm anxious to learn what they find. I should hear something over the next couple of days and will share my findings.
I noticed the same thing while I was at COTA last weekend. Had a tech from LG Motorsports (they were on site tuning a C8) take a look at it and he told me it was normal venting as you guys described. However, after sitting idle in the garage for a couple of days, I noticed more fluid leaks (fortunately, I put cardboard under the car to avoid a mess in my garage). I took the car to the dealer Thursday and I'm anxious to learn what they find. I should hear something over the next couple of days and will share my findings.
probably just venting still. When I changed my trans fluid 5 days after driving the car last, as I opened the fill valve , I could hear air escape.
probably just venting still. When I changed my trans fluid 5 days after driving the car last, as I opened the fill valve , I could hear air escape.
I always hear that, and I'm also wondering if it's air escaping or rather rushing in (since it'd have less pressure inside once tranny cools down a bit).
All this talk makes me want to change the fluid again; it's been a while, but it always comes out looking perfect..
While one of the guys from a race shop said the transmission fluid leak I saw on day 2 of my last track weekend was normal, I was a bit concerned about the fact that my transmission was still leaking a couple of days later so I took it to the dealer. The dealer said it’s normal for the leak to continue for a couple of days and that C7’s are known to leak after a heavy day on the track running MPSC2 tires in the heat. To eliminate the leak going forward, they suggested that I consider a thicker (aftermarket) fluid.
Next time I have my car in the shop, I’ll probably change to a thicker fluid.
I'm very surprised that the dealer would suggest a thicker fluid, since it might have other consequences. The maintenance manual is also pretty clear on the fluid specs, so this might possibly be used to deny warranty, too; I'd ask them. Regardless, please let us know if you end up using a different fluid : )
I have had 2 A8 Grand Sports. I tracked each one for about two years and not a single drop of fluid anywhere. Only time when I had a slight leak was from a bad trans oil pan gasket.
I have had 2 A8 Grand Sports. I tracked each one for about two years and not a single drop of fluid anywhere. Only time when I had a slight leak was from a bad trans oil pan gasket.
Thanks for the feedback all. I'm going to have a catch can installed on the tranny next week. I'll keep the thread updated after the next couple track days after the install.
So had a catch can installed by a local Corvette shop. Here's some pictures. Heading out for the track tomorrow so will be interesting to see if there's no more tranny fluid on the garage floor when I get some, or if there's some fluid in the catch can when I go to drain it at my next engine oil change. Will update this thread.
Pictures don't show a lot, but what they did was buy a kit from somewhere, remove the vent from the top of the tranny, drill two holes and tapped them, then installed a metal plate with a 90 degree male fitting on it, then run a hose down to the catch can which they mounted behind the wheel well liner for the right rear wheel. Making it easy to access to drain. The can empties by screwing the knurled nut in clockwise, then back counterclockwise to stop draining.
BTW, the tranny was full when they changed the tranny fluid, so that goes to show that what looks like a lot of oil on the ground, in reality really isn't that much.
However I HATE oil on the ground in my garage, and also couldn't in good conscience sell a car to someone with a fluid leak.
I don't care how GM hypes these things, they are not "race" cars. Yeah, buzz around a track a couple laps, but don't press long and/or hard.
Well, I've been tracking this car for eight seasons now and have gotten an enormous amount of fun out of it. And yes, I beat the hell out of it, and yes I repair it as necessary. C8 Z06 is next. I'm one of the lowest numbers on several top allocation dealers. You only live once.
Cheers.
So had a catch can installed by a local Corvette shop. Here's some pictures. Heading out for the track tomorrow so will be interesting to see if there's no more tranny fluid on the garage floor when I get some, or if there's some fluid in the catch can when I go to drain it at my next engine oil change. Will update this thread.
Pictures don't show a lot, but what they did was buy a kit from somewhere, remove the vent from the top of the tranny, drill two holes and tapped them, then installed a metal plate with a 90 degree male fitting on it, then run a hose down to the catch can which they mounted behind the wheel well liner for the right rear wheel. Making it easy to access to drain. The can empties by screwing the knurled nut in clockwise, then back counterclockwise to stop draining.
BTW, the tranny was full when they changed the tranny fluid, so that goes to show that what looks like a lot of oil on the ground, in reality really isn't that much.
However I HATE oil on the ground in my garage, and also couldn't in good conscience sell a car to someone with a fluid leak.
Nice detail. However the vent only release when pressure is built up above a certain point I assume? And we don’t know that pressure rating do we? So are you going to be collecting more overflow than needed now that it’s just an open line to the catch can?
Transmission and Diff fluid leaking
