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Is changing the filter one step in checking when there is a problem and so because there is a code, you should change the filter to try and clear it, but before you do that you need to run the flush to try and also remove all particulate with the filter change? So is there routine filter change AND a filter change that needs flush to try and clear a debris problem?
There may be an out somewhere else in the service manual but I don't have access to it. Perhaps there is another procedure for maintenance only but you would think that Document ID 5384826 would state something if that is the case.
That's why I was hoping for some justification from technicians that didn't do the procedure (other than them not thinking it is necessary).
The housing is aluminum and a post on another forum said the screws are also aluminum. The material on the new screws is thread locker. That is probably why they need to be replaced.
He also didn't chase the threads (or didn't show it) which is called out in the procedure to remove the old thread locker and contamination. There is a caution note associated with that step to make sure the screws get properly torqued.
Thought about the fact that there are aluminum bolts supplied with the filter because it the "Thread Locker" material. Perhaps it's more than "Thread Locker" as supplying bolts just for that would appear to be an overkill. Just looking at the size bolts, 53 in-lbs (4.4 ft-lbs) is far from stressing aluminum. Wonder if it's a special "Thread Oil Sealent" similar to what is used on head bolts that go into the water jacket? Perhaps it has to be compatible with DCT fluid?
And agree, residual "stuff" left in the filter holder threads could easilly take some in-lbs to overcome so you'd have a false low torque.
I'll repeat what I said in Post #16:
Couple of things make me think most (initial higher) wear occurred in that first ~1000 miles.
First: Gears typically have matted and worn high spots in 500 to max 1000 miles. Companies making performance differentials mostly say 500 miles and some 1000 before using the car for towing.
Second: Another (higher initial) wear area is the multidisc clutches. Could feel my 1st gear clutch slipping when coming to a slow stop for about 1000 miles. Now at 3000 it is hardly noticeable. Stopped pulling both paddles when coming to a stop after the 1st month.
So IMO No Way does it take 7500 miles. GM probably used 7500 because it matches the time engine oil must be changed- 12 months or roughly 7500 miles. Clutch disks, just like in a "slushbox automatic" continue to have some small wear but in a typical "automatic" can last >100,000 miles.
The Owner's Manual footnote 4 says change DCT fluid after max 3 years. So like engine oil there is a maximum time which requires a fluid change. I have no concern changing at ~4000 miles (free) and next year will have ~8000 miles. Could change the filter again (and if I thought it was a warranty issue would) BUT think I will wait for the next filter change at 3 years when I'll have ~12000 miles and do it with a fluid change.
Sorry about your mistaking my post to be a repeat of yours. Yes, some of it is, but end point is not the same.
You say disregard GM's and Trans Manufactures procedure.
I disagree with that. Reasoning. I do so is because of my work background, and seeing the results of not following procedures.
I look at it as Manufacture of trans knows more than GM about break-in procedure at this time, as they are the ones that developed Trans,
Per what I've read about trans, an how it works, along with part tolerances, an multi clutch plates & gears, etc. , I'll stick with what GM & Trans Manufacture recommend, maintenance wise, as between them, they've done the testing! that led to their conclusion, about maintaining it.
I'll always recommend to others to follow Manufacture's procedures, as best as possible.
Best as I can tell, an having 7,5000 mile service done on my C8, Fluid Change is not required, at 7,500 miles, only the Filter, with top off of fluid only due to what lost with filter replacement.
I got the Filter and Fluid top off for Free.
When directed to the flush or leak test, it then reads:
Flush reads: This procedure is used to flush the transmission fluid through the filtration system before a repair is performed that may have been caused by debris in the fluid.
Leak Test reads: This procedure is used to test the transmission for leaks after a repair.
We are not repairing, we are changing the filter and/or a fluid drain and replace (these are called maintenance).
Sorry about your mistaking my post to be a repeat of yours. Yes, some of it is, but end point is not the same.
You say disregard GM's and Trans Manufactures procedure.
I disagree with that. Reasoning. I do so is because of my work background, and seeing the results of not following procedures.
I look at it as Manufacture of trans knows more than GM about break-in procedure at this time, as they are the ones that developed Trans,
Per what I've read about trans, an how it works, along with part tolerances, an multi clutch plates & gears, etc. , I'll stick with what GM & Trans Manufacture recommend, maintenance wise, as between them, they've done the testing! that led to their conclusion, about maintaining it.
I'll always recommend to others to follow Manufacture's procedures, as best as possible.
Best as I can tell, an having 7,5000 mile service done on my C8, Fluid Change is not required, at 7,500 miles, only the Filter, with top off of fluid only due to what lost with filter replacement.
I got the Filter and Fluid top off for Free.
Do as you wish, so will I. My experience and knowledge (including watching the Petty Race team break-in their differentials on a dyno to achieve max efficiency) tells me 1000 miles is sufficient for gears.
The clutches plates and disks should be well matted and any excess initial wear over in <1000 miles. That is when I felt the somewhat rough 1st gear clutch slippage below about 3 mpg become perfectly smooth when coming to a slow stop. Automatic ("slush box") transmissions have similar clutches in most gears. Sure there is slight wear after the 500 miles initial break-in GM recommended, but as I said many automatic ("slushbox") transmissions go well over 100,000 miles with the same multidisc wet clutches.
But understand that is your feeling. Well see next year if there is any information saying I should change the filter again for warranty reasons when I'll have between 7000 and 8000 miles . BUT I will get the free filter installed this year with about 4000 miles. All else being the same, I'll wait to 3 years with about 12,000 miles to change filter again when I replace the fluid (as required at that time.) Be foolish to replace the fluid in 3 years without replacing the filter.
And I agree the latest info is at 7500 miles a fluid change is not required only a flush procedure. That is not a fluid replacement. I'll let the excellent Corvette tech I use decide if he is going to do that!
So your position is the technicians following the DCT filter change procedure and doing the flush are are misinterpreting the first step?
Or are you saying that the technicians should be allowed to skip steps in the procedure if they think the steps aren't necessary?
Or do you think there is another procedure besides Document ID 5384826 that they are following?
Thought about the fact that there are aluminum bolts supplied with the filter because it the "Thread Locker" material. Perhaps it's more than "Thread Locker" as supplying bolts just for that would appear to be an overkill. Just looking at the size bolts, 53 in-lbs (4.4 ft-lbs) is far from stressing aluminum. Wonder if it's a special "Thread Oil Sealent" similar to what is used on head bolts that go into the water jacket? Perhaps it has to be compatible with DCT fluid?
And agree, residual "stuff" left in the filter holder threads could easilly take some in-lbs to overcome so you'd have a false low torque.
I don't think it's sealant on the screw threads. The holes look like they are blind so wouldn't have fluid behind them.
It's quite common to have fasteners come pre-coated with thread locker. It speeds up the assembly process and enhances quality control to not have the tech putting the thread locker on during assembly. Likewise, it may be more cost effective to just replace the screws than to spend the time cleaning them up and putting thread locker on.
There could be reasons for the low torque on the fasteners, especially if the aluminum housing doesn't have thread inserts but it needs to withstand multiple installation and removal cycles. And the lower torque could be the reason for the thread locker. The less the preload the less friction preventing the fastener from loosening.
Do as you wish, so will I. My experience and knowledge (including watching the Petty Race team break-in their differentials on a dyno to achieve max efficiency) tells me 1000 miles is sufficient for gears.
The clutches plates and disks should be well matted and any excess initial wear over in <1000 miles. That is when I felt the somewhat rough 1st gear clutch slippage below about 3 mpg become perfectly smooth when coming to a slow stop. Automatic ("slush box") transmissions have similar clutches in most gears. Sure there is slight wear after the 500 miles initial break-in GM recommended, but as I said many automatic ("slushbox") transmissions go well over 100,000 miles with the same multidisc wet clutches.
But understand that is your feeling. Well see next year if there is any information saying I should change the filter again for warranty reasons when I'll have between 7000 and 8000 miles . BUT I will get the free filter installed this year with about 4000 miles. All else being the same, I'll wait to 3 years with about 12,000 miles to change filter again when I replace the fluid (as required at that time.) Be foolish to replace the fluid in 3 years without replacing the filter.
And I agree the latest info is at 7500 miles a fluid change is not required only a flush procedure. That is not a fluid replacement. I'll let the excellent Corvette tech I use decide if he is going to do that!
I don't think breaking-in a rear Dev break-in is any thing like DCT gears. Dif gears are machined with break-in groves machined into them. Haven't seen DCT gear(s) to see if they have wear-in groves in them. Dif-Gears may have.
We did break-in runs on rear gears back end the 60s. That's been done for years, reasons for them.
Any-way,, like you say do what you think,
I'll stay with procedures put in place by more knowledgeable people than me..
I don't think breaking-in a rear Dev break-in is any thing like DCT gears. Dif gears are machined with break-in groves machined into them. Haven't seen DCT gear(s) to see if they have wear-in groves in them. Dif-Gears may have.
We did break-in runs on rear gears back end the 60s. That's been done for years, reasons for them.
Any-way,, like you say do what you think,
I'll stay with procedures put in place by more knowledgeable people than me..
With regards to the procedures, this document says to replace the DCT filter at 7,500 miles or when the OLM says to change the oil:
The owners manual says the car is ready for track use after 1500 miles, implying break-in is complete by then. So I'd say you're safe doing the first DCT filter change anytime between1500 miles and 7500 miles.
I don't think breaking-in a rear Dev break-in is any thing like DCT gears. Dif gears are machined with break-in groves machined into them. Haven't seen DCT gear(s) to see if they have wear-in groves in them. Dif-Gears may have.
We did break-in runs on rear gears back end the 60s. That's been done for years, reasons for them.
Any-way,, like you say do what you think,
I'll stay with procedures put in place by more knowledgeable people than me..
The DCT has the same gears as any manual transmission, mostly very efficient spur gears! The high spots on the very low friction involute profile that has very little sliding will be gone in less that 500 miles. Have never seen a reference saying quality gears need more than 500 miles. Be pretty poorly made gears. Tremec makes standard transmission for large trucks etc. They know what they are doing! Provided pic below.
You can think of what I am doing (and I'm sure what many will do at one year with only 3000 to 4000 miles) and having the dealer change the filter FREE similar to folks who change oil earlier than GM recommends. Can't hurt. If you think there is some magic to the 7500 miles than change it again at year 2. But if only putting on 3000 to 4000 miles a year (as will many) per footnote 4 page 290 of the Owner's Manual the fluid MUST be changed at 3 years maximum. So would be foolish NOT to change the filter then, when replacing the DCT fluid.
^^^^
Yep, hidden by the none cut away section. Currie, one of the leading differential suppliers, said to break-in the high performance gears I have in their shortened 9 inch Ford Rear my Street Rod for 500 miles!
"At Currie, we recommend the initial break-in to start by driving normally for 15-20 minutes (no bun outs, hard starts, or highway driving), then letting the vehicle rest for 30-minutes, never going over 50 miles without letting it cool. Towing and high speeds should also be avoided until after break-in (300-500 miles)"
When directed to the flush or leak test, it then reads:
Flush reads: This procedure is used to flush the transmission fluid through the filtration system before a repair is performed that may have been caused by debris in the fluid.
Leak Test reads: This procedure is used to test the transmission for leaks after a repair.
We are not repairing, we are changing the filter and/or a fluid drain and replace (these are called maintenance).
There is another thread/post on this forum where the dealer performed the flush/filter/leak test for the first free service and the labor code(s) for the flush &leak test were not paid by GM. If the flush & leak test were required for the filter change (maintenance), GM would have paid the labor code(s). see below.
post #12 GM will only pay for the filter replacement and top off. The first C8 we sold we did the flush, leak test, and filter change GM wouldn't pay the claim said just filter and top off. by Corvette ED; 06-13-2021 at 01:39 PM.
I think I have a plan, I'm going to pass on the free filter and do it myself. I love working on my own cars and really don't like anyone else to so here is what I'm going to do. I'm not on the clock and have a Quick Jack, so the plan is to drop the filter and carefully clean everything to operating room level and reassemble, but not pull the fill plug. I'll lower car and pull the airbox and just add the full quart of fluid to the top of the DCT. That way I know I replace the 4-6 oz. of fluid lost and I don't need to run the car and go through gear changes and then inside of 5 minutes to check level until fluid is running down the side of the DCT. Majority of a quart is far from an overfill since you can do two full quarts and I'll be adding approximately 26 oz. In watching the Conti video there were a few things that made me cringe, like using a dental pick to dig the O-ring off of the aluminum cover, possibly scratching or gouging it, and I also didn't see him put any fresh fluid on the new O-ring, nor clean out the housing threads with a chaser or even spray some brake clean into them. At 3,000 miles most if not all of the initial break-in of the transmission has occurred so I'm going to freshen her up.
I think I have a plan, I'm going to pass on the free filter and do it myself. I love working on my own cars and really don't like anyone else to so here is what I'm going to do. I'm not on the clock and have a Quick Jack, so the plan is to drop the filter and carefully clean everything to operating room level and reassemble, but not pull the fill plug. I'll lower car and pull the airbox and just add the full quart of fluid to the top of the DCT. That way I know I replace the 4-6 oz. of fluid lost and I don't need to run the car and go through gear changes and then inside of 5 minutes to check level until fluid is running down the side of the DCT. Majority of a quart is far from an overfill since you can do two full quarts and I'll be adding approximately 26 oz. In watching the Conti video there were a few things that made me cringe, like using a dental pick to dig the O-ring off of the aluminum cover, possibly scratching or gouging it, and I also didn't see him put any fresh fluid on the new O-ring, nor clean out the housing threads with a chaser or even spray some brake clean into them. At 3,000 miles most if not all of the initial break-in of the transmission has occurred so I'm going to freshen her up.
I'd do basically the same but for the refill of the lost fluid. The side fill plug seems so much easier to use with a small tilt of the car (driver's side up) and the back driver side wheel off. A simple gravity flow through a tube is all that is needed. Just mho.
^^^
Funny, many months ago I had speculated that lifting the drivers side was a "possible way" to even add two quarts! As usual made a pic!
Someone recently posted he used that approach for adding 2 quarts and it worked! My pic shows the funnel and hose on the outside of the car. I recall filling the 9 inch Ford dif on my street rod by clamping the funnel to a 6 foot ladder! That fluid is viscous so took a long time BUT gravity works. For the C8 should be able to open the trunk hatch and get the hose in position past the engine. But then you'll need a sky hook to hold the funnel!
PS: I installed a low restriction air filter and it's only part of what is needed to get to the top fill plug. It's a bit of a PIA!
There is another thread/post on this forum where the dealer performed the flush/filter/leak test for the first free service and the labor code(s) for the flush &leak test were not paid by GM. If the flush & leak test were required for the filter change (maintenance), GM would have paid the labor code(s). see below.
post #12 GM will only pay for the filter replacement and top off. The first C8 we sold we did the flush, leak test, and filter change GM wouldn't pay the claim said just filter and top off. by Corvette ED; 06-13-2021 at 01:39 PM.
Yes, I saw that post. But it makes sense that he didn't get paid for the labor codes separately. The labor for the flush and leak check is included in the filter replacement labor code. It would have been double-dipping to pay for them separately. Just like if he had tried to include the labor codes for removal and installation of the rear shear plate, fluid level check, etc. separately GM would deny those claims.
^^^
Funny, many months ago I had speculated that lifting the drivers side was a "possible way" to even add two quarts! As usual made a pic!
Someone recently posted he used that approach for adding 2 quarts and it worked! My pic shows the funnel and hose on the outside of the car. I recall filling the 9 inch Ford dif on my street rod by clamping the funnel to a 6 foot ladder! That fluid is viscous so took a long time BUT gravity works. For the C8 should be able to open the trunk hatch and get the hose in position past the engine. But then you'll need a sky hook to hold the funnel!
PS: I installed a low restriction air filter and it's only part of what is needed to get to the top fill plug. It's a bit of a PIA!
I'm just going to use a squeeze bottle and tubing at the fill port. I have a fluid pump but I don't want to risk cross-contamination.
Yes, I saw that post. But it makes sense that he didn't get paid for the labor codes separately. The labor for the flush and leak check is included in the filter replacement labor code. It would have been double-dipping to pay for them separately. Just like if he had tried to include the labor codes for removal and installation of the rear shear plate, fluid level check, etc. separately GM would deny those claims.
I think I have a plan, I'm going to pass on the free filter and do it myself. I love working on my own cars and really don't like anyone else to so here is what I'm going to do. I'm not on the clock and have a Quick Jack, so the plan is to drop the filter and carefully clean everything to operating room level and reassemble, but not pull the fill plug. I'll lower car and pull the airbox and just add the full quart of fluid to the top of the DCT. That way I know I replace the 4-6 oz. of fluid lost and I don't need to run the car and go through gear changes and then inside of 5 minutes to check level until fluid is running down the side of the DCT. Majority of a quart is far from an overfill since you can do two full quarts and I'll be adding approximately 26 oz. In watching the Conti video there were a few things that made me cringe, like using a dental pick to dig the O-ring off of the aluminum cover, possibly scratching or gouging it, and I also didn't see him put any fresh fluid on the new O-ring, nor clean out the housing threads with a chaser or even spray some brake clean into them. At 3,000 miles most if not all of the initial break-in of the transmission has occurred so I'm going to freshen her up.
I like your plan!!!
I have added 2QTS through the top to 3 C8's, takes me 1HR/42MIN. I would suggest jacking up the car on one side, removing the left rear wheel, remove the side fill plug, and gravity fill through a tube. This how I will do it in the future.
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That fluid is viscous so took a long time BUT gravity works. For the C8 should be able to open the trunk hatch and get the hose in position past the engine. But then you'll need a sky hook to hold the funnel!
