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Hi all so I bought a 2021 C8 with 10000 miles on it. As soon as I received it I took it to a dealer to get the oil changed and also to find out about getting the DCT filter changed. So I am the third owner and the previous two Owners did not do an oil change or the DCT filter changed. Really not sure why but anyway when I went to the dealer they said my free oil change had expired ( by two days) of course no big deal I’ll get that done. However the DCT filter change was gonna cost me a lot. Total for the oil and DCT oil and filters changed was $1000.
I asked the tech if he did a DCT flush and he said no wasn’t needed. So far no problems with the engine or the DCT car has run great since I got it. My question is should the tech have performed the flush or not. Current mileage is 16000 miles. Do I need to get it done now or can I wait until 22500 miles? Once again the car has operated great and haven’t had any problems whatsoever. Thx for any input.
Yes, the tech should have performed the Hydraulic System Flush. It's the first step every time the DCT filter is changed. It's amazing how uninformed some dealer service departments and techs are. I think the issue may be that GM has changed the procedure fairly recently, and that techs don't bother to look in the service manual for jobs they "already know how to do." So they never notice that the procedure has changed.
Here's what the service manual says they're supposed to do. If you want to make your service write unhappy, take this to him and ask why the tech didn't follow the service manual.
On another note, did they change the DCT oil? If so, they ripped you off on that, too. The DCT fluid doesn't need to be changed until 3 years are up, regardless of mileage. And if they DIDN'T change the DCT fluid, they really ripped you off, because $1,000 for just an oil and filter change and DCT filter is way too high.
Hi all so I bought a 2021 C8 with 10000 miles on it. As soon as I received it I took it to a dealer to get the oil changed and also to find out about getting the DCT filter changed. So I am the third owner and the previous two Owners did not do an oil change or the DCT filter changed. Really not sure why but anyway when I went to the dealer they said my free oil change had expired ( by two days) of course no big deal I’ll get that done. However the DCT filter change was gonna cost me a lot. Total for the oil and DCT oil and filters changed was $1000.
I asked the tech if he did a DCT flush and he said no wasn’t needed. So far no problems with the engine or the DCT car has run great since I got it. My question is should the tech have performed the flush or not. Current mileage is 16000 miles. Do I need to get it done now or can I wait until 22500 miles? Once again the car has operated great and haven’t had any problems whatsoever. Thx for any input.
The term for what you are asking about is the Hydraulic System Flush and its the first step in the DCT filter change procedure. When you used the the term DCT flush - was it clear what you are asking about? There is no such thing as a procedure to flush the transmission, and that even appears in a tech link article. "There is not a required fluid flush procedure and the transmission should not be flushed." The tech probably understood but maybe not. Given that its already done and you are at 16000 miles, I really don't know what you need to do. Its not about the warranty at this point. Its about the car. The procedure for doing the change includes a caution (see post 2) that if the service is past the interval, you should change the filter before doing the HSF due to the danger of clogging the filter. If you suspect the HSF has never been done, and since you just had the filter changed, I think it might be ok to get the HSF now. Or it might be ok to wait til 22500, but do the HSF before the filter is changed at that time.
Here is the link to the article that says no fluid flush procedure (not to be confused with the Hydraulic System Flush)
Well after looking at my dealer invoice for the oil and DCT change 1)Engine oil and filter came to $150 2) DCT the tech only changed the filter and replaced the lost fluid 1qt. The oil was $65 and the filter was $170. Total was $385 for parts.
Labor came to $405. The rest was shop bs and tax.
I didn’t realize the fluid needed flushing after 3 years. I was under the assumption the fluid got flushed after every filter change. I looked in the owners manual and didn’t see it. I guess I’ll be doing more maintenance on the car after these charges. Maybe not a flush but definitely the oil change and the DCT filter. Thx for the input.
Well after looking at my dealer invoice for the oil and DCT change 1)Engine oil and filter came to $150 2) DCT the tech only changed the filter and replaced the lost fluid 1qt. The oil was $65 and the filter was $170. Total was $385 for parts.
Labor came to $405. The rest was shop bs and tax.
I didn’t realize the fluid needed flushing after 3 years. I was under the assumption the fluid got flushed after every filter change. I looked in the owners manual and didn’t see it. I guess I’ll be doing more maintenance on the car after these charges. Maybe not a flush but definitely the oil change and the DCT filter. Thx for the input.
I still think you may be confused, or maybe it is just your use of terms. The fluid is never, ever "flushed". At three years the fluid is drained and filled. There is no fluid flush. But the Hydraulic System Flush is to be done at every DCT filter change. Also, while your tech may or may not have done it, even when it is done, it will not appear as a line item on your invoice. That is, you will just see that the procedure to change the DCT filter was performed. The invoice will not articulate all the steps, which include the HSF, filter remove and replace, level check, and a leak test. But if you tech is not doing the HSF as part of that, then he is not following the procedure.
10,000 miles and the engine oil has never been changed? You sure?
if so some D bag just reset the olm a couple times without doing a change, so easy to do on this car too.
Find out for sure if the hydraulic system flush (not transmission flush) was or was not performed when they changed the DCT filter. If they didn't do it ask them to do it and replace the filter again. If they believe it isn't necessary ask them to state that in writing.
When I had my two year DCT filter replaced I was told the computer controlled flush was not now required per GM. They even pulled up the instructions on their computer and could see line 1 stating flush so they knew about it. I checked with two other dealer service reps and they also said no computer flush. New filter and replace fluid. I know on other threads this has been brought up and someone said if tranny needed repair/replacement it would be under warranty. That is fine if it goes out at home but I travel in it and don't want to be stuck. Does anyone know how to contact GM to verify this change in procedure? Any contact information would be appreciated. Also those that have had the filter changed, did you have the computer controlled flush and actually know/see them do it. Or was it just a filter change.
When I had my two year DCT filter replaced I was told the computer controlled flush was not now required per GM. They even pulled up the instructions on their computer and could see line 1 stating flush so they knew about it. I checked with two other dealer service reps and they also said no computer flush. New filter and replace fluid. I know on other threads this has been brought up and someone said if tranny needed repair/replacement it would be under warranty. That is fine if it goes out at home but I travel in it and don't want to be stuck. Does anyone know how to contact GM to verify this change in procedure? Any contact information would be appreciated. Also those that have had the filter changed, did you have the computer controlled flush and actually know/see them do it. Or was it just a filter change.
If the procedure was changed, I would expect that 1) the online procedure that the techs us would change - in other words those digital up to date manuals, 2) for any reason that was not true - then by what other path would the dealer and tech come by this information? A phone call? No. There would be a technical bulletin alerting them to the change. As you know, if you have been following the threads, there is a very recent update to the procedure, dated 2023 at the bottom of the page. Not only did they retain that wording, they doubled down on it, saying if that if the change is being done late, after the prescribed interval, then replace the filter before, rather than after the HSF. No way all that is accidental or unintended. Its difficult dealing with service writers and tech when they are so sure. But you might try to ask for proof that the procedure changed, or ask them to show you their own on-line procedure. If the are using and up to date one, it will be in there. Oh wait, the already did, and it already was. I don't know what to say.
When I had my two year DCT filter replaced I was told the computer controlled flush was not now required per GM. They even pulled up the instructions on their computer and could see line 1 stating flush so they knew about it. I checked with two other dealer service reps and they also said no computer flush. New filter and replace fluid. I know on other threads this has been brought up and someone said if tranny needed repair/replacement it would be under warranty. That is fine if it goes out at home but I travel in it and don't want to be stuck. Does anyone know how to contact GM to verify this change in procedure? Any contact information would be appreciated. Also those that have had the filter changed, did you have the computer controlled flush and actually know/see them do it. Or was it just a filter change.
It is my understanding that dealerships are no longer required to send removed DCT filters to GM for analysis. Is it possible that when this happened some dealerships also put their own spin on the DCT filter replacement procedure and decided that the hydraulic system flush was also not required? Just a thought. My take on all of this is that those dealerships either don’t want to take the time (about 10 minutes) to do the flush, or really have convinced themselves that it is not necessary, irregardless of what the written procedure states. Either way, it appears to be a disservice to the paying customer.
When I had my two year DCT filter replaced I was told the computer controlled flush was not now required per GM. They even pulled up the instructions on their computer and could see line 1 stating flush so they knew about it. I checked with two other dealer service reps and they also said no computer flush. New filter and replace fluid. I know on other threads this has been brought up and someone said if tranny needed repair/replacement it would be under warranty. That is fine if it goes out at home but I travel in it and don't want to be stuck. Does anyone know how to contact GM to verify this change in procedure? Any contact information would be appreciated. Also those that have had the filter changed, did you have the computer controlled flush and actually know/see them do it. Or was it just a filter change.
As you just stated it is still in the required service procedure at line 1 so it is not your responsibility to contact GM for anything. If you dealer is trying to tell you the opposite of what the GM service procedure is then I would ask THEM for the written instructions from GM that the hydraulic system flush is no longer mandatory. You'll find out very quickly that they were talking out of their...
We had a master tech from a huge dealership come on these forums and claim the same thing. Says he never does it on customers cars and its not required by GM. After he was pressed on it and to provide evidence backing what he was saying he literally disappeared from the forum.
When I had my two year DCT filter replaced I was told the computer controlled flush was not now required per GM. They even pulled up the instructions on their computer and could see line 1 stating flush so they knew about it. I checked with two other dealer service reps and they also said no computer flush. New filter and replace fluid. I know on other threads this has been brought up and someone said if tranny needed repair/replacement it would be under warranty. That is fine if it goes out at home but I travel in it and don't want to be stuck. Does anyone know how to contact GM to verify this change in procedure? Any contact information would be appreciated. Also those that have had the filter changed, did you have the computer controlled flush and actually know/see them do it. Or was it just a filter change.
My slice on it is... Some dealers are interpreting the "no more sending the dirty DCT filter back to GM" as no more hydraulic DCT flush too.
As you just stated it is still in the required service procedure at line 1 so it is not your responsibility to contact GM for anything. If you dealer is trying to tell you the opposite of what the GM service procedure is then I would ask THEM for the written instructions from GM that the hydraulic system flush is no longer mandatory. You'll find out very quickly that they were talking out of their...
We had a master tech from a huge dealership come on these forums and claim the same thing. Says he never does it on customers cars and its not required by GM. After he was pressed on it and to provide evidence backing what he was saying he literally disappeared from the forum.
So, they charge time by the 'book' but they skip steps. So, they are overcharging the customer. Sounds very shady.
So, they charge time by the 'book' but they skip steps. So, they are overcharging the customer. Sounds very shady.
Not only that, you only lose a few ounces of fluid with the filter change, adding any fluid isn't required, but they charged him $65 for a full quart. Going through the side level hole, you can't add a quart of fluid to a full transmission.
I still think you may be confused, or maybe it is just your use of terms. The fluid is never, ever "flushed". At three years the fluid is drained and filled. There is no fluid flush. But the Hydraulic System Flush is to be done at every DCT filter change. Also, while your tech may or may not have done it, even when it is done, it will not appear as a line item on your invoice. That is, you will just see that the procedure to change the DCT filter was performed. The invoice will not articulate all the steps, which include the HSF, filter remove and replace, level check, and a leak test. But if you tech is not doing the HSF as part of that, then he is not following the procedure.
OP…let’s simplify what the “Hydraulic System Flush” is and does. Before they touch anything they plug in their commuter into the OBD port and initiate a program that opens the solenoids in the transmission the program simply circulates the transmission fluid through the DCT filter they are trying to collect the last of the break-in contaminants in the filter before changing it. After the program runs they disconnect the cable from the OBD port then raise the car to remove the DCT filter and replace it with new filter. Some (not all) dealers then add back transmission fluid to replace the small amount lost when they took the filter out. But it’s not necessary per GMs service manual.
OP…let’s simplify what the “Hydraulic System Flush” is and does. Before they touch anything they plug in their commuter into the OBD port and initiate a program that opens the solenoids in the transmission the program simply circulates the transmission fluid through the DCT filter they are trying to collect the last of the break-in contaminants in the filter before changing it. After the program runs they disconnect the cable from the OBD port then raise the car to remove the DCT filter and replace it with new filter. Some (not all) dealers then add back transmission fluid to replace the small amount lost when they took the filter out. But it’s not necessary per GMs service manual.
Your description of the Hydraulic System Flush is accurate, and it only takes 10 minutes or so! But the version of the procedure I have for the DCT Filter Change has a call, near the end, to a "Transmission Fluid Level and Condition Check". That "sub-procedure" includes checking and topping off the fluid. So, unless it was deleted, or there is some caveat I overlooked, it is "necessary".
Your description of the Hydraulic System Flush is accurate, and it only takes 10 minutes or so! But the version of the procedure I have for the DCT Filter Change has a call, near the end, to a "Transmission Fluid Level and Condition Check". That "sub-procedure" includes checking and topping off the fluid. So, unless it was deleted, or there is some caveat I overlooked, it is "necessary".
AGREED….but I was trying to keep it simple for the OP and not get into the weeds.
Yes, its a lots simpler than the name sounds. But the total DCT filter change procedure, including the sub-procedures that are called, has many steps. Here is my simplified summary of the whole thing:
1. Perform the Hydraulic System Flush. (10 minute computer controlled process while the engine is idling)*
2. Remove and replace the DCT external canister filter.
3.Perform the Transmission Fluid Level and Condition Check (involves running the engine, cycling through the gears, then checking and topping off the fluid).
4. Perform the Hydraulic System Leak Test (invoke the Hydraulic System Leak Test and follow the procedure on the screen. Completes in 1 minute)
*a note recently added to the procedure says if the service is being performed after required maintenance interval for the DCT filter change, then reverse the order of steps 1 and 2.
DCT Flush
