What parts do I need besides the fluid, and new filter? Do I need any gaskets, or items like that? I'm going to buy the parts and have someone else do the fluid drain and refill.

 

The transmission pan gasket is reusable if in good condition. But, how can you tell the condition of the gasket before removing it? I purchased a new gasket before I attempted to service my transmission. Although my old gasket looked OK, I replaced it. The part number for the gasket is: 24260071

Before pulling the transmission pan, pull the rubber filler plug out first. This way you know that you will be able to refill the transmission when you are ready to refill it. If you wish to replace the filler rubber plug, it is part number: MPN4522155059. This cost of the plug is $4

 

Why would you do that instead of getting them to do the "Triple Flush" to get rid of the as much of the substandard fluid as possible and introduce fresh fluid?

 

Because most dealers are doing the same thing , drain , refill, get up to temp , rinse and repeat 2 more times

@joemessman I bought a new gasket but really did not need it as the pan litterly popped free when last bolt was removed

You will have to drill out the two pop rivets that hold the old gasket in place . I put mine back together without the rivets as the gasket is thick and does not move around
I did not loosen the trans mount bolts but in retrospect i should have as the rear pan bolts are a pain

Dave

 

I thought that you had to hook up some sort of flush unit to it per the procedure? At least that is what I saw happened.

 

Yep thats the proper way .... using a fluid exchange machine but i heard first hand that some smaller dealers did not have the equipment , or techs did not use it hence the name tripple flush lol

I would rather go to a trans shop that uses the BG flush machine but in the end , I was able to just fill and empty mine 3 times and feel confident that there is enough of the new fluid in the trans

I did not have the shudder but I can tell you my trans does shift way better

Even a fluid exchange machine does not guarentee that there will not be any of the old fluid mixing with the new

Dave

 

Mine is a 2019 that came with the proper fluid to begin with. Butt.....the dealer I have my car service at flushes the system after draining the old fluid. There is some kind of flushing agent he uses that runs throughout the system to clean it up. I'm not a mechanic. That is as specific as I can be.

 

The proper machine is necessary and I make sure you have it before I make a service appointment. The drop pan way should be called the "Triple Drop" service.

For me, I'd prefer not to fool with that mess in the garage without a hoist. Not sure how much money it would save.

So they say.

It will not guarantee that. I think it would guarantee more than dropping the pan. Maybe if you do it 3 times, it might be fine but it would be more labor intensive and messy. Only way to get it all out is to disassemble the trans and clean it up and reassemble. Fluid exchange is probably the neatest and time saving option.

 

Maybe for you that would be the a good choice but for me I love working on my car plus I have a Quick Jack

I only dropped the pan once as I was replacing my internal transmission harness , there is a TSB about the harness having a short in the thermistor circuit which pops an annoying code stating that the temp sensor is not working

I did the filter and fluid exchange at the same time plus I was able to see if there was any particles in the pan which after 50,000 miles there was none . If I was not doing all of this I would have just pumped the fluid out all three times

For the other two times there is no point in dropping the pan again as I used a 10 dollar fluid pump from harbor freight to remove the fluid . It works great !

I also measured exactly what I took out which was 8 quarts , pumping it right into the empty bottles I had from the first change , using this method I know I got 99 % everything that was in the pan and what was in the filter/ valvebody each time with no messy cleanup .

You are right the only way to guarentee 100% exchange is to remove the trans and take it apart , then you also need to flush the converter on the bench , way more work and it's just not nesssary when doing a fluid exchange. And any Fluid Exchange machine is not going to do any better than what I did

You are making an assumption that it was messy ...🤣 actually it was not other than wearing a pair of gloves and I had it done in an hour .

But ... all of this means nothing because the OP stated he has a 2019 which means he already has the new fluid and is only doing a filter and fluid change , his orginal question was does he need anything else other than the fluid and filter , he can replace the pan gasket if he wants but there really is no need to as the gasket is reusable and pop riveted to the pan

Dave

 

For a 19,if the mileage is right, I'd agree to drop the pan. I really would change the gasket anyway. Fluid is more expensive and I hate it when it it leaks. I consider gaskets like condoms. I don't like to reuse either.

 

The triple flush process as described in the TSB does not include dropping the transmission pan to replace the transmission filter. The filter should be replaced at 45K miles according to the maintenance schedule.

A DIY can flush the old fluid out of the converter using the following procedure:
1 Remove and replace the trans pan and filter and refilling with new fluid.
2 Disconnect the trans cooler line at the trans cooler. It was easy on my Stingray.
3 Start the engine and run it long enough to flush a quart of fluid out thru the cooling line
4 Stop the engine
5 Refill trans with one quart of fluid
6 Repeat steps 3, 4 and 5 until old fluid is flushed out of converter
7 Reconnect trans cooling line
8 Refill trans fluid to proper level
9 Done

I used the above procedure when I serviced my A8

 

That would be 16 quarts you would have to do that process for ...
Dave

 

Your estimate of 16 quarts is very close.

My C7 is the Stingray so it has only one trans cooler.

After replacing the filter and pan, I refilled the trans with seven (7) quarts of new fluid. It is my opinion that the seventh quarts overfill the trans by half a quart or so. During the converter flushing process, it took another five (5) quarts of fluid before bright red fluid started to come out of the cooling line. I flushed thru another quart for good measure and used another quart due to my sloppiness. I used a total of ~14 quarts.

By the way, I used one of those inexpensive fluid transfer hand pumps to drain the old fluid out. That way when I pulled the trans pan, I avoided making a mess. I made other messes but not that one.

 

You forgot one VERY important thing. If you are going to remove a line by unscrewing, I would hit it generously with Kroil. I learned the HARD way to get penetrant on it at least a day before. Going to get the brake lines replaced on the 2017 F250. It isn't that old but I am still going to hit the threads before.

 

For sure those threaded line connectors can be tough to remove. And a lubricating product like you suggested helps.

The trans cooler on the C7 Stingray takes push-on lines with retainer clips. They too can become tough and rusty, but mine were clean. The step-by-step process that I posted is a high-level outline with the details omitted. For example, I omitted the details about setting the correct fluid level (e.g., fluid temp, shifting thru gears).

 

Great thread. Could someone provide some more specifics about which ATF cooler line to disconnect. I own a 2015 Z51 A8, built late June/July 2015, so I have two ATF coolers, one in the rear quarter panel and a second up front. A photo of which connector to remove would be great, but I know that's asking alot. Thanks.

Some quick background info. I bought the car with 5400 miles, had the local dealer with the proper GM equipment do the triple flush as soon as I got the car home from Ohio to the Boston area. When I inquired about having it done again, now that I just crossed 20,000 miles, they told me it would cost me just over $500.00. Really !!!! I own a quick jack and do all my other regular maintenance, the ATF fluid change and flush will just be one more to add to the list.

 

I don't follow. The triple flush was done to get rid of the old fluid. Why did you need to do it again?

 

I was told by the dealer that if I take the car to HPDE track day events, it needs to be done in 20,000 mile intervals ?

 

My 2017 C7 is the base Stingray trim, and I can only write about my work on it. I have no experience with other trims such as your Z51.

The Stingray has just one trans cooler; it is located inside the driver side rear wheel well housing. To gain access to the cooler, I removed the wheel followed by removing the wheel housing liner. The trans cooler is then exposed and the coolant line is easy to access. On your Z51, there may be a superior way to disconnect the trans coolant line for the purpose of flushing out the old fluid from the torque converter. Maybe the front coolant is easier to access. What is the direction of the trans fluid flow in the Z51? If it flows through the rear cooler first and then makes it way to the front cooler, then it would be superior to disconnect the coolant line at the front cooler for the purpose of flushing out the old fluid from the torque converter and its two coolers.

Many forum members may suggest a triple flush. However, the triple flush process as written in the TSB excludes pulling the pan, replacing the trans filter, and cleaning off material collected by the magnets. And, what happens to all the debris collected by the magnets during a triple flush? I believe the triple flush is good on a fairly new and low milage car. But my Stingray had 40K miles by the time I did the first trans service. It was time to replace the filter and clean out the stuff collected by the magnets.

 

dcova, thanks very much for taking the time to reply. Your response is helpful and has some good suggestions, I'll have to try and figure out which direction the ATF is "flowing". I'd like to be able to do that without pulling off lines and turning on the engine, but if that's the last resort, not a huge deal.

I think I am going to go after pulling the line off the rear cooler first. I am not convinced the front one is either "better" or easier to access. I just had the rear lower valance off, working on the dreaded AFM exhaust actuator valves, replacing the driver's side, and ended up getting a pretty good look at the rear ATF cooler in the quarter.

I have the quickjack lift system, so getting it sufficiently far up in the air and level to the ground isn't an issue.