it is a simple test.

fill it with water and pressurize it.

if it leaks, go back to the drawing board.

 

I agree....The Ghibli is not even in the same class as the MC20, I will agree the Ghibli had A Lot of problems. but that was just 1 model, the older QP with the F1 transmission was another story...yikes. The German ZF transmission are used in many brands of cars, been a really good transmission overall. Maserati doesn't make transmissions, just like GM doesn't make the the DCT. I think since GM designed the LT2 and now the new Z06 engine which are just amazing, I am surprised they didn't design their own DCT, or maybe they did and just sublet it out to Tremec to build them.

 

sounds like the trans module. I had to have mine replaced.

 

sorry fat fingers. I took delivery on 11/1/21. It looks like it will need a new DCT at 401 miles.

 

Nope not that easy! Aluminum castings have internal porosity, some in most! It has been noted the leaking (more like seeping in most reports) DCT cases only happened when the oil is hot. Guess could fill with the same DCT oil at ~200F and wait and see if any seepage is found but could take a while! There are NOT large leaks. Or perhaps as we have to do with our 2500 psi cylinder welding shielding gas aluminum regulators, high pressure gas. BUT even in that case it was NOT obvious bubbles in a water tank but a slow pressure reduction noted over 15 minutes!

Tremec identified the areas likely to seep fluid and apparently made changes, Probably how and where the aluminum gets to that area of the mold to reduce the chance of small pores.

 

We know forum members have reported a number of different issues with their DCT, and many of those issues have been reported by more than one member. While we don;t know the true frequency of occurrence for any of those issues, the reporting is more frequent and more consistent than for other components of the car. So its reasonable to ask if there have been any design changes (or manufacturing or production changes) that might address some of the issues that owners have encountered. In any case, the OP asked if there were any engineering improvements to the DCT, which I interpret to be a design change. I have not seen any reports of GM disclosing a design change to the DCT. Are there any? If not, then the answer is "no, there is no information on DCT engineering improvements". If someone has information on any GM design (or manufacturing or production) changes to the DCT since the start of production, that would be of interest.

 

I know for a fact they changed the casting half way through 2021. I saw the information at the Chevy parts counter. Have them pull up the screen for 2021 and look for a DCT pan and or gasket, they give you a choice. It will say "with reinforcement" or "without reinforcement". You can also see the additional bolts (and the count of them) on the new style case. As far as why they made the change, that is completely up to speculation, but they did indeed change the transmission case design.

 

idk man, there are millions of cars on the road and this is the first I’m hearing of oil leaking through metal haha. They messed something up.

 

Not me, I was selling Corvettes when the C5 was introduced and our very first C5 came off the truck with a trail of blood (ATF) coming from the transmission and it was determined the rear cover was porous.

 

My car has 401 miles on it. Not sure what day it was built. I think it was a Wednesday.

 

I agree, I've owned many Honda's over the last 35 years and not one leak form their aluminum cast transmissions/transaxles. Also no excuse to have oil leaking from a pan gasket in this day and age.

 

A friend of mine had a Honda in the mid 80s and some of the aluminum head had actually eroded away to the point that the only fix was a new head. Hondas aren't made by God working second shift.

 

Yep, as mentioned aluminum casting have porosity! Some very small and don't cause an issue. There are methods to fill pores used for some products as in the aerospace and military BUT may not be compatible with the high temp DCT oil. (You can google vaccum impregnation.) Another method and one Tremec has apparently used for newer cases is to identify the areas where the porosity is causing seepage (see pic) and change the way the casting is filled. May not recall but a bigger problem was some aluminum C8 wheels where the porosity was excessive and some came to the surface (see pic.)

SIDEBAR
We had a welding shielding gas cylinder regulator were a high percentage of casting were received with undetectable nonvisible porosity. It was only found after assembly when tested with ~2500 psi. And then only by a leak down test that took about 10 to 15 minutes! Expensive as the casting was machined and regulator was assembled.

There was another unusual product with an aluminum housing that I recall was solved by only allowing one distributor to buy! We sold our business to the largest welding company in the World at the time from Sweden. They had sold some unique products in the US prior that were imported by a few distributors. One was a MIG welding push pull gun that had an air operated pull motor in an aluminum handle. It had a unique ability to vary the welding speed with the gun trigger than controlled the built in air motor drive. That air was also used to cool the gun nozzle allowing a small front end with good access. Had an advantage to trailer manufactures as the trigger speed control lever allowed the welder to deal with part gaps. One region manager called and said he want to sell it directly to a large user. Recall I told that segment business manager fine. He got a price from Sweden, marked it up like 2:1 and quoted. Turned out is was much cheaper than what the fabricator had been paying.

The distributor who had been selling the gun and consumable parts like tips called me and politely said, "You can sell those yourself BUT let me explained what I do." Those aluminum gun cases all have porosity and leak air! I disassemble and coat the pats with sodium silicate (called water glass) to seal them. I sell reassembled guns and replacement parts that are coated! Recall telling that segment business manager to withdraw the quote we're only going to sell those guns to that one distributor!

The seepage in the C8 DCT appears to be only from a few areas after the fluid is Hot. Tremec said the redesigned the casting.


May not recall but there was a period where the C8 aluminum wheels had to be checked as a number had visible porosity! Mine were checked and were fine.

 

Sounds like a number of improvements on the Z06. 5:38 in on this video:


“higher spec clutch plates, improved oiling, deeper sump and improved pickup”

No idea if this is only the Z06 version of the transmission or if 2023 versions will all get some changes as well. But clearly GM has made improvements.

 

Mmmmm, so does that mean the 2023s will be getting a revised DTC? I wish they would make the transmission filter a spin off filter (like an oil filter), that would make things so much easier. I have a feeling if so, some people may volunteer to wait for a 23 instead of a 22.

 

How about transmission failure with 37 miles on the odometer? I'd call that a defect.

 

Those sound more like performance improvements. DCT issues so far look like quality control problems.

 

Not all defects are engineering defects.

 

This doesn’t mean that at all just as the new Z06 engine isn’t going to be on the 2023 Stingray.
People are going to volunteer to get a 2023 because they can’t get a 2022.

 

That's pretty obvious when it comes to the engine. The DCT is different on the other hand. The DCT should be the same as the Stingray except for a shorter final drive-ratio. To have a completely different DCT in the Z06 would not be cost effective and make it more expensive than what it is now.

But, I for one if I know there will be revisions in the DCT for the better I will inquire with my C8 specialist for a 2023 instead, hell what's a couple more months.

The C7 Z06 and C7 ZR1 shared the same transmission.