DIY 722.9 7G-tronic 7-speed automatic transmission service thread
Member
Joined: May 2008
Posts: 125
Likes: 1
From: Chicago
2007 GL450 2005 C55 2002 C32 sold 2001 ML320 sold
Hoping to do this in the next 2 weeks. The fluid change that is, not the rear end stuff 
I would not have dreamt about taking on this job without these instructions and the experience of the forum members so thank you all in advance.
I have one missing link though and that is what is the part number of the new transmission pan? I have a GL450 and my pan is the old one based on the pictures in the PDF. I am assuming all 722.9 transmissions are the same so the part number would be the same.
If there are any updated part numbers to those kindly provided in the PDF, please let me know also.
I would not have dreamt about taking on this job without these instructions and the experience of the forum members so thank you all in advance.
I have one missing link though and that is what is the part number of the new transmission pan? I have a GL450 and my pan is the old one based on the pictures in the PDF. I am assuming all 722.9 transmissions are the same so the part number would be the same.
If there are any updated part numbers to those kindly provided in the PDF, please let me know also.
Junior Member
Joined: Nov 2009
Posts: 37
Likes: 1
'10 E550 Coupe, '67 230 SL, '06 E350 4-Matic, '75 911S, '04 Porsche Boxster S, '04 Cayenne Turbo
Hoping to do this in the next 2 weeks. The fluid change that is, not the rear end stuff
I would not have dreamt about taking on this job without these instructions and the experience of the forum members so thank you all in advance.
I have one missing link though and that is what is the part number of the new transmission pan? I have a GL450 and my pan is the old one based on the pictures in the PDF. I am assuming all 722.9 transmissions are the same so the part number would be the same.
If there are any updated part numbers to those kindly provided in the PDF, please let me know also.
I would not have dreamt about taking on this job without these instructions and the experience of the forum members so thank you all in advance.
I have one missing link though and that is what is the part number of the new transmission pan? I have a GL450 and my pan is the old one based on the pictures in the PDF. I am assuming all 722.9 transmissions are the same so the part number would be the same.
If there are any updated part numbers to those kindly provided in the PDF, please let me know also.
It might be worth your time to subscribe to http://epc.startekinfo.com/epc/home.jsp which will give you the exact part number that you need based on your VIN. If I remember correctly, it is only a few dollars a year.
Member
Joined: May 2008
Posts: 125
Likes: 1
From: Chicago
2007 GL450 2005 C55 2002 C32 sold 2001 ML320 sold
Thank you Gild. 
I subscribed and got the part numbers i need. As a bonus, that subscription appears to be free for passenger cars even though i had to enter a credit card.
It also allowed me to print off the data card for the cars i have which gave me all the options fitted, the engine and transmission numbers etc which i had been looking for for ages.
I'll be onto the parts sites and or dealers this week so i am ready to do the transmission job next week.
I subscribed and got the part numbers i need. As a bonus, that subscription appears to be free for passenger cars even though i had to enter a credit card.It also allowed me to print off the data card for the cars i have which gave me all the options fitted, the engine and transmission numbers etc which i had been looking for for ages.
I'll be onto the parts sites and or dealers this week so i am ready to do the transmission job next week.
Thread Starter
Super Moderator
Joined: Dec 2006
Posts: 2,403
Likes: 64
From: Camas, WA
2007 C230SS; 2014 ML350 BT
Thank you Gild. I subscribed and got the part numbers i need. As a bonus, that subscription appears to be free for passenger cars even though i had to enter a credit card.
It also allowed me to print off the data card for the cars i have which gave me all the options fitted, the engine and transmission numbers etc which i had been looking for for ages.
I'll be onto the parts sites and or dealers this week so i am ready to do the transmission job next week.
I subscribed and got the part numbers i need. As a bonus, that subscription appears to be free for passenger cars even though i had to enter a credit card.It also allowed me to print off the data card for the cars i have which gave me all the options fitted, the engine and transmission numbers etc which i had been looking for for ages.
I'll be onto the parts sites and or dealers this week so i am ready to do the transmission job next week.
Good luck, and I hope this writeup helps. Please don't hesitate to ask any questions you have.
MBWorld Fanatic!
Joined: Feb 2009
Posts: 5,537
Likes: 8
2006 C350 Sport 6MT
Waz up John!!!!!
I'm reaching 52k miles. I guess it's time for an Tranny Fluid/Filter change?
Hey hey what's that up there?? I'm gone for a week and you guys are talking about me?
Matt that was a good one 
I'm reaching 52k miles. I guess it's time for an Tranny Fluid/Filter change?
Hey hey what's that up there?? I'm gone for a week and you guys are talking about me?
Matt that was a good one
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MBWorld Fanatic!
Joined: Sep 2010
Posts: 1,434
Likes: 4
From: Raleigh, NC
2005 C230K, 2019 Honda CR-V, '74 Lotus Europa
I was going to wait for my wife's 2006 C230 to reach 60k miles before changing the tranny fluid, but now I'm thinking better of it. I looked over the earlier posts on this thread and now I feel like an idiot (not a new feeling for me).
First, I have studiously avoided any kind of automatic transmission DIY my entire car owning life - and so far, that has actually worked pretty well so far. I try not to have cars with autos and by the time my wife's transmission NEEDS service, it's time to get rid of it anyway. But now, she has a much nicer car (and more expensive) than usual so I want to make sure I treat all of it right.
I assume that I don't have a TC drain plug, but Glyn said they might have been reintroduced. In order to find out if I have one, do I put the car on stands and bump the starter watching for the drain plug in the bell housing access port? That seems pretty hit & miss.
I don't know where to add the fluid. My car doesn't have a dipstick tube for the tranny...
I don't have a STAR diagnostic system or an infrared thermometer. Are they really necessary to drain the fluid and refill it? If so, it sounds like this may be more of a job of an indy shop...
I'd appreciate anybody who can straighten me out on this.
Thanks!
First, I have studiously avoided any kind of automatic transmission DIY my entire car owning life - and so far, that has actually worked pretty well so far. I try not to have cars with autos and by the time my wife's transmission NEEDS service, it's time to get rid of it anyway. But now, she has a much nicer car (and more expensive) than usual so I want to make sure I treat all of it right.
I assume that I don't have a TC drain plug, but Glyn said they might have been reintroduced. In order to find out if I have one, do I put the car on stands and bump the starter watching for the drain plug in the bell housing access port? That seems pretty hit & miss.
I don't know where to add the fluid. My car doesn't have a dipstick tube for the tranny...
I don't have a STAR diagnostic system or an infrared thermometer. Are they really necessary to drain the fluid and refill it? If so, it sounds like this may be more of a job of an indy shop...
I'd appreciate anybody who can straighten me out on this.
Thanks!
Last edited by ncmudbug; Jan 1, 2011 at 09:59 PM.
Thread Starter
Super Moderator
Joined: Dec 2006
Posts: 2,403
Likes: 64
From: Camas, WA
2007 C230SS; 2014 ML350 BT
Just pull the little rubber cover out of the transmission bell housing and use an appropriate sized socket and breaker bar and have a friend turn the crankshaft while you look for the plug. It is very small, but noticeable.
Thread Starter
Super Moderator
Joined: Dec 2006
Posts: 2,403
Likes: 64
From: Camas, WA
2007 C230SS; 2014 ML350 BT
I was going to wait for my wife's 2006 C230 to reach 60k miles before changing the tranny fluid, but now I'm thinking better of it. I looked over the earlier posts on this thread and now I feel like an idiot (not a new feeling for me).
First, I have studiously avoided any kind of automatic transmission DIY my entire car owning life - and so far, that has actually worked pretty well so far. I try not to have cars with autos and by the time my wife's transmission NEEDS service, it's time to get rid of it anyway. But now, she has a much nicer car (and more expensive) than usual so I want to make sure I treat all of it right.
I assume that I don't have a TC drain plug, but Glyn said they might have been reintroduced. In order to find out if I have one, do I put the car on stands and bump the starter watching for the drain plug in the bell housing access port? That seems pretty hit & miss.
I don't know where to add the fluid. My car doesn't have a dipstick tube for the tranny...
I don't have a STAR diagnostic system or an infrared thermometer. Are they really necessary to drain the fluid and refill it? If so, it sounds like this may be more of a job of an indy shop...
I'd appreciate anybody who can straighten me out on this.
Thanks!
First, I have studiously avoided any kind of automatic transmission DIY my entire car owning life - and so far, that has actually worked pretty well so far. I try not to have cars with autos and by the time my wife's transmission NEEDS service, it's time to get rid of it anyway. But now, she has a much nicer car (and more expensive) than usual so I want to make sure I treat all of it right.
I assume that I don't have a TC drain plug, but Glyn said they might have been reintroduced. In order to find out if I have one, do I put the car on stands and bump the starter watching for the drain plug in the bell housing access port? That seems pretty hit & miss.
I don't know where to add the fluid. My car doesn't have a dipstick tube for the tranny...
I don't have a STAR diagnostic system or an infrared thermometer. Are they really necessary to drain the fluid and refill it? If so, it sounds like this may be more of a job of an indy shop...
I'd appreciate anybody who can straighten me out on this.
Thanks!
To answer your other question, I hate to be so blunt but NO, you can NOT service the 7G without STAR or an infrared thermometer. This transmission is VERY picky with fluid level, and it must be checked an adjusted just as described in the documents I posted, or you will likely suffer serious transmission damage. So, if you are not absolutely comfortable buying the correct tools, and following the procedures, please find a good indy to do it for you.
Junior Member
Joined: Nov 2009
Posts: 37
Likes: 1
'10 E550 Coupe, '67 230 SL, '06 E350 4-Matic, '75 911S, '04 Porsche Boxster S, '04 Cayenne Turbo
Yes, it is an M12 size. I ended up buying the ready-made tool that John recommended. I think if you make your own, you'll need something like a rubber or cork washer to seal against the bottom of the pan. And you need a way to attach the hose going to your pump.
Junior Member
Joined: Apr 2010
Posts: 15
Likes: 1
From: So Cal
CLS550
I have used a custom adaptor during my tranny service. I bought it from a local race shop. It was like $10. Its one of these anodized fittings.
Like this..
http://www.jegs.com/webapp/wcs/store...-1&showValue=3
Like this..
http://www.jegs.com/webapp/wcs/store...-1&showValue=3
Hate to see what the fluid looks like coming out at 60K.
Senior Member
Joined: May 2006
Posts: 292
Likes: 0
both of my indie mechanics(30 years MB exp. total) told me that there is really no need drop the pan and replace the filter. It's only if your pan is leaking around the edges(filter failure or seal damage) should you even have to mess with it. Yuor filter will continue to do it's job, some say even even better with fresh fluid sloshing around...but by looking at your ATF you will be able to notice if you have an issue with your tranny almost immdiately..from things such as contamination from other fluids(separation), to metal shavings from tranny parts scrubbing together due to low fluid. if you don't see any of that in your fluid after you drain it, then leave the pan alone. it's worth it to just change the tranny fluid regularly and ride until it croaks versus constantly dealing with tranny fluid leaks and drips after tampering with the tranny pan.
So far my indies are on point. no leaks, no shift issues and I'm at 215,000miles on the clock and only changed the fluid once since I bought it at 75,000.
As regular maintenance I always check the level to be sure I'm good.
So far my indies are on point. no leaks, no shift issues and I'm at 215,000miles on the clock and only changed the fluid once since I bought it at 75,000.
As regular maintenance I always check the level to be sure I'm good.
MBWorld Fanatic!
Joined: Feb 2009
Posts: 5,537
Likes: 8
2006 C350 Sport 6MT
While your at it you might as well change it no? If you do it properly and clean it well then I doubt you'll have a problem. I honestly wouldn't risk running the same filter for a long time.
--------------------------------------
Here is a video of what happens when you don't maintain your transmission well. Guy probably believed MB's BS claim of lifetime tranny fluid.
http://www.youtube.com/watch?v=pFgfHkK_FsY
Here is the assembly of our 722.9 transmission.
Pretty cool video.
http://www.youtube.com/watch?v=AGbmS5tXSq8
--------------------------------------
Here is a video of what happens when you don't maintain your transmission well. Guy probably believed MB's BS claim of lifetime tranny fluid.
http://www.youtube.com/watch?v=pFgfHkK_FsY
Here is the assembly of our 722.9 transmission.
Pretty cool video.
http://www.youtube.com/watch?v=AGbmS5tXSq8
Thread Starter
Super Moderator
Joined: Dec 2006
Posts: 2,403
Likes: 64
From: Camas, WA
2007 C230SS; 2014 ML350 BT
If you read back at my posts closely, I actually DID NOT have a pan leak. The fluid was leaking from the bell housing. It was just fluid that accumulated in the bell housing from draining the torque converter. Fashioning a simple shield to keep fluid from running down the bell housing will keep that from happening.
I would NOT advocate just changing the fluid and not the filter. IMO it is cheap insurance for a VERY expensive transmission.
I would NOT advocate just changing the fluid and not the filter. IMO it is cheap insurance for a VERY expensive transmission.
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Find new Indy mechanics very quickly. Sounds like 30 X 1 years experience & learned nothing. 
You must change the filter. We are playing with hydraulics here. Biggest killer of hydraulics = dirt or wear debris.
What if your filter looks like this one from a 722.6
As John says this is a very expensive transmission.
You must change the filter. We are playing with hydraulics here. Biggest killer of hydraulics = dirt or wear debris.
What if your filter looks like this one from a 722.6
As John says this is a very expensive transmission.
