I really like this advice and it's backed up by multiple sources within gm

 

Here's a question for the DCT Filter audience.....My recently acquired 2021 HTC (8/2021 in-service date) has 2500 miles on it now. Previous owner had an engine oil /filter done in Nov, 2021, at about 800 miles. No record of a DCT filter change. Also, no issues with the trans. All good.

Is the "free" DCT filter change still available to me? Is there a time limit, even if the mileage is still below 7500? I'll be at least a year or more getting to 7500.

Any real-world experiences would be most appreciated!

 

Which part of what you bolded is not a fact.? The part about needing to change it again if you changed it early? Or the part about being SOL if you did not change it again and had a transmission failure? Yeah, maybe they won't deny the claim so that is a conclusion. But its a conclusion based on some strong evidence from the Tech Link article:"Recommended miles intervals should be followed. If a customer elects to have the filter changed before 7,500 miles (12,000 km), it should be changed again at 7,500 miles (12,000 km). Check the maintenance schedule in the appropriate Service Information. TIP: Filter change information should be shared with your service advisors and service management. GM will be reviewing maintenance records on transmission warranty claims. Lack of maintenance on the canister filter cartridge may affect warranty coverage."

That last part suggests that there is a good chance that warranty claim will be denied if the maintenance schedule was not followed.
https://gm-techlink.com/?p=17254

 

The answer is yes, you will still receive a free DCT filter change.

 

Could do what I'm doing. I had my engine oil/filter changed on GM's dime year one when the OLM said 5% engine oil life left. That has to be done, in my case it was 12 months (max time OLM will allow) with ~3000 miles. One reason I did early was because a number of folks had DCT CELS early and dealer called GM with code and was told do a flush and for many it was gone. I also had my own observations re 1st gear clutch smoothness changing at ~1000 miles so thought it was prudent.

Plus looking at the Owner's Manual as ALL C8's whatever year, at year 3 regardless of miles you MUST have all 11 quarts of DCT fluid changed. Thought heck I'll have about ~10,000 miles and ~6000 on that 1st year changed filter. Good time to have the DCT Filter changed again. Not exactly GM's 7500 miles but for me good enough to make a case if needed. Also good time to have the Dealer Tech change engine oil/filter (as OLM will say to do that,) fill with new DCT fluid AND rather than have ~7 oz of old fluid in the filter and filter housing it will be new fluid.

Discussed with the C8 Corvette tech this past August, year 2 when I paid for just having required engine oil/filter change. He thought good plan. That is all on my dime as the 11-quart change would be. To perform the 11 quart change he has to access the DCT fluid fill plug by removing the aluminum aero panel "shear plate" anyway so why not! Suggest as minimum that would be smart. Not perfect but provides some extra DCT protection.

Your Car Your Choice.

Here are some pics:

To access the DCT Fluid fill plug Tech must remove the aluminum, aero Panel (GM also calls shear plate as it provides a structural function.)

Pic of plate removed when tech changed my DCT filer year 1 with ~3000 miles

GM says ~ 0.2 Liters = 7 oz DCT fluid in filer housing. To access the DCT fluid fill plug (and filter) the aero panel must be removed.


PS: I just noticed when I posted this old pic I made ~ 2020 it says: DCT Filter MUST be changed during this 1st Oil Change! Now this is typical GM conflicting statements, both in the Owner's Manual and elsewhere. If I am ever questioned for the 6 months I'll have between when I reached 7500 miles on my C8 (just recently) and Next August when I'll have the DCT filter changed again I'll just print this pic and say, just following what was published! BTW my Tech would never question it would be GM questioning the dealer!

 

The free change is good for up to two (2) years or 7,500 miles. The question here is whether the original owner used that free service when the oil filter was changed. If that is the case, you would most likely have to pay for the transmission filter change at 7,500 miles.

 

I had my DCT filter changed at 4600 miles before GM extended the first service to 2 years and before this was much of a controversy.
I contacted Chevrolet Customer Support via their messaging system and asked them if I needed to change the DCT filter again at 7500 miles. They said I was good untill the next schedulred service interval. I took a screenshot of their response and saved it for my records.

If you decide not to have your DCT filter changed again at 7500 miles I recommend you get something in writing from GM stating it is OK.

 

What Andybump said. I probably should have said "high likelihood" that you are SOL. I've seen warranty claims denied for much less. But in a nutshell, not following the maintenance schedule, and then having something go wrong, is going to make it much easier for GM to deny warranty coverage.

 

I have years of experience collaborating with dealerships to include brokering deals where dealerships sold in-house performance parts.

I also have years of experience driving cars and blowing up engines in them lol.

I can tell you that dealerships do not approve or deny warranty claims. That's general motors.

And the absolute first thing that general motors will ask for is the service history on any large ticket drivetrain item like an engine or transmission.


Now they may be willing to give Goodwill and give concessions if you didn't follow the maintenance schedule quite perfectly but the further away you get from it the less and less likely you are to receive any good will.

 

Totally agree stay within the warranty guidelines.
I changed the engine oil, oil filter and DCT filter at 3000 miles for my peace of mind on my 2021.
At 7300 miles did the change again per GM guidelines. If I have a DCT issue my cars service history record is with in the guidelines.

 

Why not just perform the service as indicated in the service manual? No more of these early and extra fluid / filter changes. If the fluid / filter really needed to be changed earlier than scheduled, we would see engines and transmissions blowing up which GM would be on the hook for replacing under warranty. If that were happening, GM would quickly revise the service schedule but they haven't had to.

 

There has been a significant amount of transmissions that have been replaced over something very simple as debris getting stuck within the valve passages and in the solenoids but unfortunately there is no repair procedure for that other than trying to flush it out and so the entire transmission gets replaced.

For me to simply avoid my car being out of commission for that long and the inconvenience of it I had no issue flushing and replacing the filter early and it was indeed soaked with debris.

For oil changes Corvette has an interesting history on the c7 of in fact getting the initial oil change interval wrong. They actually went back after silicone contamination was found from the adhesives in the dry sump system which is the same system we use and determined that a 500 MI oil dump was required.

Because of their rather poor track record on proactively identifying this as an issue I decided to check my oil quality at 640 MI and low and behold it had visible metals in it as well as silicone contamination.

I definitely am not suggesting that everybody has to do what I did but I am very glad that I did it again mostly out of convenience that I just rather not have to deal with a dealership replacing engines and transmissions. ... As well as the aftermath that can sometimes come with it which is a car that comes back not yet fully ready for the road.

 

GM has issued a direction to dealers that says if the DCT filter is changed "early" it must be changed again at 7500 miles. That's not an assumption, it's a fact.

That (red part), directly contradicts the Techlink memo provided a couple of weeks ago by GM to dealers. That memo said if changed early, it MUST be changed again at 7500. You can argue about what the definition of "early" is, but I don't think you can reasonably argue that 5500 miles isn't early. GM has made it pretty clear they want the break in wear particulates that accumulate for the first 7500 miles out of there.

In addition to Techlink, people from the Corvette DCT team also state that if changed early it should be changed again at 7500 miles, two years in a row at Carlisle.

I respect your knowledge and much of what you've posted on the forum, but telling a dealer that "this guy on the Corvette Forum told me I could drive it another 17,500 miles before changing the filter" isn't going to hold much water compared to the direct instructions from GM Techlink.

 

Interesting, since there's no silicone sealant used in the C8's dry sump system. It's a welded plastic tank.

 

The silicone in the C7s was probably related to the engine doubt it was the external dry sump tank. May have been rear main crank seal or front crank seal or other places in the pan to block. Or the intake manifold ends where it commonly used. I have seen a robot applying a silicone bead on the pan instead of using a gasket, maybe that was used for the C7 pan to block?

When assembling the ZZ 502502 engine for my Street Rod they provided a tube of high temp silicone sealant and said use it NOT the "rubber end seals." See pic from instructions.

SIDEBAR
The reason it was probably only for dry sump C7s is that is where the oil foam would go from the pan that GM said might occur with the original oil fil IF the engine was operated at sustained speeds. Then the foam would be sucked into the dry sump tank by the scavenge pump. To get all oil out of the pan it sucks a lot of air as well. In fact foam might be more likely to occur as oil and air go thru the scavenge pump. Then the foam would leave the top of the dry sump tank with the air that was sucked in as well. The air is "burped" thru a hose to the air intake tube.
The wet sump has no such hose. I found the last sentence in that November 24, 2014 bulletin interesting. It said "The oil foam has no effect on engine durability."

Had to cover their *** for not requiring the change on wet sumps or my car where it was NOT required! In fact the issue was that oil foam would condense it the air intake tube and run down to the air filter and drip on the ground. It was that contamination they were trying to avoid.

MY CHECK
The bulletin that came out ~14 months after I got my early C7 Z51 in September 2013. As I had with all my Vettes (and street rod) I changed the oil early ~1000 miles. So I wondered 14 months later when the bulletin came out did I have any issue. Although I did not drive the car at "sustained high speed" I did hit redline in lower gears after break-in (a number of times before the oil change.) I had looked at the incidence of oil foaming and it is common in oil pumps So the oil/air scavenge pump could be a significant source.

I installed an aFe low restriction air intake system that included a larger filter housing, larger oiled cotton filter and different air intake tube. I looked very carefully and not a drop of oil on the OEM filter or air intake tube.

 

Got the invoice from a very helpful dealer employee and confirmed that at 5200 miles all they did was change the oil and do a multi check, Thus here is the approach for next week. You charged me $70,000 plus for a car, and in that transaction you promised me a FREE transmission filter at 7500 miles. Well, the car has 7,500 miles and it and I'm here for my free filter. It is not my problem that your employee failed to even address this issue when I picked the car up. Have a nice day.

Bill

 

May very well be the other silicone gaskets then and sealants

 

With my '22 Z51 HTC at 300 miles I got a CEL and "idle creep disabled" message. Car always drove fine and CEL cleared later the same day. I did some online research and decided to simply wait to have the first service done at the scheduled 7,500 mile mark. Actually had it done at 7,900 miles since my son and I were on a short road trip. The car has always run fine and the CEL never returned. Car now has 16,000 miles and things remain good. Different strokes for different folks....

 

Yeah I totally can't disagree that the great majority of folks will be absolutely fine following the maintenance schedule. I mean technically that's why they have the maintenance schedule.

I just got weird about this car and also wanted to check what was going on inside the engine and perhaps this one out of my three c8s had this issue. Go figure

 

Thanks for that clarification. I agree, the part of my post that you highlighted in red does contradict what the manual says, as well as GM written and verbal advice. I thought I made that clear in the part of my quote that I highlighted in green just above, which are pretty much the same points you repeated in your post. In any case, the red part was in the context of someone who wants to ignore the GM advice or interpret it differently. While I did not advocate that, I think it reasonable to point out that if one does that, based on some rationale about wear in debris shedding and filter loading, they still need to realize that they cant go full 22500 miles beyond the mileage where the filter was changed.