DIY: G37 Automatic Transmission Fluid Change, Pan Drop/Clean
08-05-2016, 01:52 AM
#47
Registered Member
I'm considering this DIY but I have a question about the measurements of each drain and the last step.
Is there a reason why each drain is less and less? To me it would make sense that if you drain 5.5qts you refill 5.5qts. Is there a reason why you would fill more than you drain?
The last step states that you need to run the vehicle while opening the refill plug and let drain 1.25-1.5qts until dripping. Based on where the refill plug is, what's stopping all the fluid from draining out?
I'm trying to make sense of the logic here lol. I've done my front diff, rear diff & transfer case but this DIY just boggles my mind a little.
Is there a reason why each drain is less and less? To me it would make sense that if you drain 5.5qts you refill 5.5qts. Is there a reason why you would fill more than you drain?
The last step states that you need to run the vehicle while opening the refill plug and let drain 1.25-1.5qts until dripping. Based on where the refill plug is, what's stopping all the fluid from draining out?
I'm trying to make sense of the logic here lol. I've done my front diff, rear diff & transfer case but this DIY just boggles my mind a little.
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MStrike (10-10-2021)
08-05-2016, 08:49 AM
#48
I'm considering this DIY but I have a question about the measurements of each drain and the last step.
Is there a reason why each drain is less and less? To me it would make sense that if you drain 5.5qts you refill 5.5qts. Is there a reason why you would fill more than you drain?
The last step states that you need to run the vehicle while opening the refill plug and let drain 1.25-1.5qts until dripping. Based on where the refill plug is, what's stopping all the fluid from draining out?
I'm trying to make sense of the logic here lol. I've done my front diff, rear diff & transfer case but this DIY just boggles my mind a little.
Is there a reason why each drain is less and less? To me it would make sense that if you drain 5.5qts you refill 5.5qts. Is there a reason why you would fill more than you drain?
The last step states that you need to run the vehicle while opening the refill plug and let drain 1.25-1.5qts until dripping. Based on where the refill plug is, what's stopping all the fluid from draining out?
I'm trying to make sense of the logic here lol. I've done my front diff, rear diff & transfer case but this DIY just boggles my mind a little.
If you look at my findings, the total amount drained, minus the total amount added (including the final "run until it starts to drip") came out equal.
As far as why you don't drain out the pan, there are two plugs in the pan, one is a full drain plug, the other is a fill tube that goes up into the pan a couple inches, this is the plug you remove when you do the final drain while it's running, this leaves the proper level in the pan at operating temp.
HTHs.
Last edited by blnewt; 08-05-2016 at 08:56 AM.
08-05-2016, 11:01 AM
#49
Registered Member
I thought the same thing, but just figured it's just the way the fluid builds up when operational and being turned off. Just put it into one of those "it's a mystery, just roll with it" scenarios, lol.
If you look at my findings, the total amount drained, minus the total amount added (including the final "run until it starts to drip") came out equal.
As far as why you don't drain out the pan, there are two plugs in the pan, one is a full drain plug, the other is a fill tube that goes up into the pan a couple inches, this is the plug you remove when you do the final drain while it's running, this leaves the proper level in the pan at operating temp.
HTHs.
If you look at my findings, the total amount drained, minus the total amount added (including the final "run until it starts to drip") came out equal.
As far as why you don't drain out the pan, there are two plugs in the pan, one is a full drain plug, the other is a fill tube that goes up into the pan a couple inches, this is the plug you remove when you do the final drain while it's running, this leaves the proper level in the pan at operating temp.
HTHs.
Thanks blnewt! The final drain part makes total sense now and why it won't completely drain. I guess i'll have to start collecting the tools to do this DIY, thanks again!
08-06-2016, 02:19 AM
#51
Registered Member
Thread Starter
Hello Everyone reading this thread. Let me post a quick update. So far I've driven almost 11,000 miles since the procedure was performed and transmission continues to operate really well. This was a leased vehicle and I have just purchased it out last month at the lease end (which I had extended 2 times with IFS for a total of 18 months). Hopefully this serves as a testament of my confidence in the mechanical condition of the vehicle, including the transmission component.
Now let me answer some of the questions that came up, and I apologize for possibly answering them a little late. The reason I was filling in a little more than draining out was because I was a little paranoid about potentially under filling the transmission. In theory you drain 5.5qt and you fill 5.5qt, but in practice some of the fluid gets spilled, some remains on the walls of oil drain pan after transferring to a measuring container, some absorbed by the rag, etc., - you get the idea. That's why I thought if I fill in 0.25qt or so more it would account for that. Additionally, I wanted to achieve higher dilution of the old fluid by adding a little more. IIRC calculations only about 7% of the old fluid will remain at the end of this procedure.
Like blnewt had mentioned, fill plug is where there is a tube on the inner side of the transmission oil pan protruding a few inches upwards above the bottom of the pan (pic 8 from the top). That's what prevents fluid from draining out completely and serves as a proper level of the transmission fluid while engine is operating and transmission is in P. When adjusting fluid level in the end you want it to be at least a little above the tube initially. That way when fill plug is opened fluid begins to run out until it levels with the top edge of the tube. At that point it starts dripping and that's when you put the fill plug back in and tighten it. Proper transmission fluid level inside the transmission has been reached.
The Consult II device dealers have does not read the level of the transmission fluid. It only reads the temperature of the fluid. It is the length of the tube mentioned above (pic 8) that ensures proper transmission oil level.
I didn't use new crush washers. In fact, I've never replaced a single crush washer in my life, and so far haven't had a single issue. Drain and fill plugs are different in diameter. I don't remember fill plug having a washer.
I think this is an example of a DIY where written it sounds and looks more complicated than it really is. Or perhaps it's my inability to explain it better. The key idea is that you are draining and refilling multiple times to remove as much of an old fluid as possible. Engine runs with cycling of transmission through the gears between drain/refill phases are necessary to mix the fluid. Then in the end you adjust the level by draining off excess fluid while engine is running and transmission is in P.
Now let me answer some of the questions that came up, and I apologize for possibly answering them a little late. The reason I was filling in a little more than draining out was because I was a little paranoid about potentially under filling the transmission. In theory you drain 5.5qt and you fill 5.5qt, but in practice some of the fluid gets spilled, some remains on the walls of oil drain pan after transferring to a measuring container, some absorbed by the rag, etc., - you get the idea. That's why I thought if I fill in 0.25qt or so more it would account for that. Additionally, I wanted to achieve higher dilution of the old fluid by adding a little more. IIRC calculations only about 7% of the old fluid will remain at the end of this procedure.
Like blnewt had mentioned, fill plug is where there is a tube on the inner side of the transmission oil pan protruding a few inches upwards above the bottom of the pan (pic 8 from the top). That's what prevents fluid from draining out completely and serves as a proper level of the transmission fluid while engine is operating and transmission is in P. When adjusting fluid level in the end you want it to be at least a little above the tube initially. That way when fill plug is opened fluid begins to run out until it levels with the top edge of the tube. At that point it starts dripping and that's when you put the fill plug back in and tighten it. Proper transmission fluid level inside the transmission has been reached.
The Consult II device dealers have does not read the level of the transmission fluid. It only reads the temperature of the fluid. It is the length of the tube mentioned above (pic 8) that ensures proper transmission oil level.
I didn't use new crush washers. In fact, I've never replaced a single crush washer in my life, and so far haven't had a single issue. Drain and fill plugs are different in diameter. I don't remember fill plug having a washer.
I think this is an example of a DIY where written it sounds and looks more complicated than it really is. Or perhaps it's my inability to explain it better. The key idea is that you are draining and refilling multiple times to remove as much of an old fluid as possible. Engine runs with cycling of transmission through the gears between drain/refill phases are necessary to mix the fluid. Then in the end you adjust the level by draining off excess fluid while engine is running and transmission is in P.
08-06-2016, 08:43 AM
#52
Thanks for the update sir^^^ Glad you'll be sticking around after the lease buy-out.
We've got about 15k since the ATF change and I'm also happy w/ the AT performance.
Also thanks for explaining the reason for adding more fluid, I just followed your plan and it worked just fine.
Oh, and also I'm real close to becoming a member of the "never replace your crush washer club" IIRC I think between our 2 Gs I've replaced the oil drain washer 4x (and that's a combined 150k miles, lol)
We've got about 15k since the ATF change and I'm also happy w/ the AT performance.
Also thanks for explaining the reason for adding more fluid, I just followed your plan and it worked just fine.
Oh, and also I'm real close to becoming a member of the "never replace your crush washer club" IIRC I think between our 2 Gs I've replaced the oil drain washer 4x (and that's a combined 150k miles, lol)
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MStrike (10-10-2021)
08-06-2016, 12:00 PM
#53
Thanks for the update sir^^^ Glad you'll be sticking around after the lease buy-out.
We've got about 15k since the ATF change and I'm also happy w/ the AT performance.
Also thanks for explaining the reason for adding more fluid, I just followed your plan and it worked just fine.
Oh, and also I'm real close to becoming a member of the "never replace your crush washer club" IIRC I think between our 2 Gs I've replaced the oil drain washer 4x (and that's a combined 150k miles, lol)
We've got about 15k since the ATF change and I'm also happy w/ the AT performance.
Also thanks for explaining the reason for adding more fluid, I just followed your plan and it worked just fine.
Oh, and also I'm real close to becoming a member of the "never replace your crush washer club" IIRC I think between our 2 Gs I've replaced the oil drain washer 4x (and that's a combined 150k miles, lol)
08-08-2016, 12:08 PM
#54
Registered Member
So during the process of exchanging the old fluid for new fluid it's best to overfill than under fill until the last exchange. The last exchange is when the ATF is at operating temperature and it's draining when the oil has fully expanded in volume. Therefore, it's not overfilled with cold unexpanded oil which could result in issues.
I think that makes some sort of sense as to why would you run the engine and letting it drain.
I think that makes some sort of sense as to why would you run the engine and letting it drain.
08-09-2016, 01:13 PM
#55
Registered Member
So during the process of exchanging the old fluid for new fluid it's best to overfill than under fill until the last exchange. The last exchange is when the ATF is at operating temperature and it's draining when the oil has fully expanded in volume. Therefore, it's not overfilled with cold unexpanded oil which could result in issues.
I think that makes some sort of sense as to why would you run the engine and letting it drain.
I think that makes some sort of sense as to why would you run the engine and letting it drain.
http://www.infinitig37.com/TSB/ITB11-036.pdf
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blnewt (08-09-2016)
08-09-2016, 09:47 PM
#57
Registered Member
I was doing a bit of googling and the process of changing out the ATF is similar to that of some European cars like Mercedes Benz. Plus it also helped that OP took the time to document to post this DIY and unearthed the mystery of the 7AT. Changing out the fluid is almost dummy proof as long as you put in what you take out.
08-09-2016, 11:04 PM
#58
Registered Member
Question: I have a 2010 approaching 120k miles. I'm the 2nd owner. Don't believe the ATF fluid has been changed out before.
Is it a good idea to perform the DIY w/ that much miles & the car never had ATF maintenance? I hear sometime when it is too high of miles, it is not recommended to change it out. Car seems to drive fine for the most part. Thanks in advance.
Is it a good idea to perform the DIY w/ that much miles & the car never had ATF maintenance? I hear sometime when it is too high of miles, it is not recommended to change it out. Car seems to drive fine for the most part. Thanks in advance.
08-10-2016, 12:18 AM
#59
Question: I have a 2010 approaching 120k miles. I'm the 2nd owner. Don't believe the ATF fluid has been changed out before.
Is it a good idea to perform the DIY w/ that much miles & the car never had ATF maintenance? I hear sometime when it is too high of miles, it is not recommended to change it out. Car seems to drive fine for the most part. Thanks in advance.
Is it a good idea to perform the DIY w/ that much miles & the car never had ATF maintenance? I hear sometime when it is too high of miles, it is not recommended to change it out. Car seems to drive fine for the most part. Thanks in advance.
At the very least I think I'd remove the plug for checking fluid level (not the drain plug) and get a little sample of fluid to see if it's got a burned smell or is a very dark brown. And if it does smell burned and very dark I'd proceed w/ the 3x drain & fill.
FWIW mine at 70k miles still had a red tint and smelled like seasoned ATF (not burned).
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tite_tite (08-13-2016)
08-13-2016, 12:42 PM
#60
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First of all I want to thank you guys for writing this extensive write up for how to do the fluid change service for these 7 speed transmissions especially dropping the pan since this is where the bulk of the crap resides and should be addressed with each fluid change.
Now, the question I have for the people who did this service for their 7 speed transmissions is why did you guys not use the transmission pump to replace the old fluid with new fluid through the radiator return hose for the transmission fluid?
Since the transmission starts pumping the fluid through the radiator as soon as the car starts, why not disconnect the return line from the radiator after you've filled the transmission pan with fresh fluid, have the other person start the car while you monitor and let out a quart or two through the radiator return line while the car idles, turn off the engine, put in the 1 or two quarts of clean fluid back into the pan (specifically the amount you let out through the radiator return line) and repeat this process until the fluid coming out of the radiator return line is as clean as one you're putting into the transmission pan?
Some concerns that can come up with this is that you might run the transmission dry. Since you have 5.5-6 quarts in the pan, letting 1 or 2 quarts come out through the radiator while the car is leveled and idling is not going to run the transmission dry.
I’ve done this method numerous of times on many of my automatic cars over the years, primarily good example would be my 07 M35x to which I’ve done this to when I did the full transmission fluid service for the 5 speed that's in it. Worked like a charm and did a full flush instead of the partial one like you guys do here...
Just throwing it out there...
Now, the question I have for the people who did this service for their 7 speed transmissions is why did you guys not use the transmission pump to replace the old fluid with new fluid through the radiator return hose for the transmission fluid?
Since the transmission starts pumping the fluid through the radiator as soon as the car starts, why not disconnect the return line from the radiator after you've filled the transmission pan with fresh fluid, have the other person start the car while you monitor and let out a quart or two through the radiator return line while the car idles, turn off the engine, put in the 1 or two quarts of clean fluid back into the pan (specifically the amount you let out through the radiator return line) and repeat this process until the fluid coming out of the radiator return line is as clean as one you're putting into the transmission pan?
Some concerns that can come up with this is that you might run the transmission dry. Since you have 5.5-6 quarts in the pan, letting 1 or 2 quarts come out through the radiator while the car is leveled and idling is not going to run the transmission dry.
I’ve done this method numerous of times on many of my automatic cars over the years, primarily good example would be my 07 M35x to which I’ve done this to when I did the full transmission fluid service for the 5 speed that's in it. Worked like a charm and did a full flush instead of the partial one like you guys do here...
Just throwing it out there...