Serhan's Garage

I just bought my first Corvette a week ago...a 2007 6 speed manual.

I changed the tranny fluid yesterday and while loosening the transmission temperature plug i ended up putting a small hairline crack next to this plug. I it leaks a bit from the crack. I just prepped and put a coat of JBweld.

I feel horrible..just got the car and now im so depressed. I hope the JB weld would prevent any leaks.

Worst case can just the transmission case be replaced. Costs?

Please help. Ill post a pic shortly

4SUMERZ

That is unfortunate to be sure. Anyone that does any DIY on anything has been in your shoes. Hopefully the JB Weld will work for you, and you will have no issues going forward. I have never heard of just being able to buy the case only. You could buy a used transmission, and redo it with the parts off of yours.
Either way, it would be at least $1000.00 for a used C6 manual transmission.
There are video's on You tube of many fixes of transmission cracks using JB weld and it fixed their issue.
Good luck

Nine, Frau!

Its all in the surface preparation and it being super clean. Smearing some on with it still leaking won't cure it.

Serhan's Garage

I let it drain over night and in the morning i sanded the area and sprayed and cleaned with acetone and i applied high pressure air to the crack and to the transmission fill plug.

I just put second coat and after 24 hours ill fill it with tranny fluid.

This is not how i wanted to start my corvette ownership experience.

Red08

Please let us know how it works.

Bruze

It may be okay.

I've always been leery of JB weld, or radiator "Stop Leak," etc.

One of my machine tools has an "air over oil" pressure tank that developed a crack on one of the welds after I put too much pressure in it. Below around 45 degrees the oil (dielectric) congeals and it wouldn't move, but I didn't know it at the time. It was the middle of winter and I had the heat off in that room of my shop.

A buddy suggested at least trying JB. So we did, and son of a gun if it isn't still holding up fine, years later. And the tank DOES get some pressure, maybe 5-10 PSI (unlike a tranny) whatever it takes to push oil up and out.

If prepped right, as someone mentioned, I'm betting your tranny should be fine, although I would have used a dental grinder (assuming you have room) to "V" out the crack some first.

mikeCsix

The way I see it there are two problems. One is, now that the case is cracked, it isn't as strong as it once was, so I would not drive this car very hard and make sure I had some towing insurance. The other issue is heat. The case is going to expand and contract at different rates than JB Weld, so even if you've prepped it, I expect the JB Weld will eventually fail.

You might be able to get away with having the crack welded shut, though welding aluminum will weaken it, it may be stronger than using JB weld. The question is, can these cases be welded? This is most likely a casting but I don't know enough about it so can't comment any further.

If it were my car, I would drive it sparingly while saving my money for a new transmission.

Joe B.

That's bizarre. Is the crack visible in the photos? How long is it? Are you sure some teflon tape on the threads, maybe? A v-groove couldn't hurt.

cclive

Because that area of the trans isn't highly stressed, I don't think that a small crack there does much to compromise the strength of the trans. Why not call a forum vendor like RPM and ask them what they think...there aren't too many places that have more expertise in this area.

Serhan's Garage

I didnt take a photo of the crack before the JB weld but the crack is about two inches starting from the temp sensor plug.

Bruze

It's hard to believe that simply loosening the plug would cause the case to crack. It must've been close to already cracking through, and that bit of pressure finished it. It just isn't logical otherwise.

But, who knows?

Serhan's Garage

The plug had some red solvent on it...maybe loctite? The only reason i tried removing the temp sensor plug was beacuse it was damaged and i wanted to inspect it..i should have just left it alone!

cclive

I didn't think the manual trans had a temp sensor....am I crazy here??

Bruze

I have no clue, but I am curious why a manual would have a sticker on it saying use ATF . . . ? In "the old days" they used regular gear oil.

extrapilot

investigated; results found that the Z51 and ZO6's do apparently.

AORoads

For what purpose? There is no temp gauge or reading for man trans that I know of. So, what would a temp sensor do, and where is the info going to, if not the driver?

Serhan's Garage

The DIC does provides transmission temp yo driver and the Z51 option includes a transmission cooler

cclive

The purpose of the sticker is to make it clear that the fluid should be Dexron III and not Dexron VI. Dexron VI is the current ATF but because of its' low friction properties, it isn't good in this manual trans.

cclive

In the picture, that looks like the drain plug location...is the drain plug somewhere else on this one?

Serhan's Garage

The drain plug is on the other side (passenger side)