S600 transmission uogrades
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From: Nyc
S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
S600 transmission uogrades
I have an issue with my tranny where after about 10 minutes the tranny fluid heats up and the stall converter starts slipping. My mechanic is telling me there's too many variables, he could swap out a part and the tranny could still slip. He recommends buying a used tranny for $1800 and swap it out. Now since he's dropping the tranny anyway, I want to install whatever upgrades while the tranny is out. What upgrades are there for the transmission? I'd like to upgrade the friction disc's but I can't find much info on them. Raybestos has a stage 1 kit. I dont know how much torque it can handle. If anyone knows any good upgrades I should consider please let me know. Thank you
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From: Nyc
S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
The transmission shop by my mechanic quoted me $4000 for a rebuild. My mechanic says it's cheaper and less of a hassle to just buy a used one and replace it. Only thing in really worried about is the strength of the used tranny. I'm sure a 722.6 from a s320 is not gonna be as strong as the one in the s600. I doubt even the s500 tranny is as strong. I dont know if there's part numbers and worried I'll get a weak tranny because I drive my cars HARD. I know the problem is the oil isn't flowing. I don't know if I should just ask them to flush all the fluids and see if that fixes it.
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2005 S500 Designo
$4k for a rebuild seems high to me.
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Before I spend the money on labor to drop the transmission I'd swap the fluid and filter if you haven't already. Actually I'd do it twice since you can't separately drain the converter. Swap it once, run it for 500 or 1000 miles, then do it again. You'll waste some fluid. So what. Then you'll know if your transmission is gone or not, and not be speculating.
If the transmission is in fact gone (twin turbo 12s driven hard on old fluid DO in fact eat transmissions -- known issue), then go for a rebuild. That will be worth a call to Marc at Sun Valler Mercedes (you can tell him I sent you) to answer all your questions and maybe beat the $4k quote for a box. You'll get there with labor and shipping, but you'll know a hell of a lot more about that than you do now.
Ultimately the problem tracks back to MBs decision that these were "sealed for life" transmissions that didn't need fluid services. Time has proven that silly -- I do mine of 5/50 intervals with the spark plugs and have never had an issue. 60/40 to 70/30 new fluid and filter is all you'll need.
That same decision doomed ABC systems, so if you haven't been swapping fluid and filters there, it's time to do so -- with the accumulators.
Hopefully this is all responsive.
GL
maw
Last edited by maw1124; Sep 21, 2025 at 11:43 AM.
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From: Virginia Beach
2005 S600 2005 SL600
I wonder how that “weaker” transmission lives behind all the hemi V8’s that Chrysler put it in?
Look, believe what you like.
If the transmission is slipping, and I have no idea what you mean by “the stall converter is slipping” whether you mean, the torque converter fails to lock, that you have shift flare, or what, because, the torque converter is designed to slip. That’s what it does.
But, if you believe the transmission is slipping, the first thing I would do would be to replace the conductor plate.
It’s a pretty easy DIY. I replaced the conductor plate in the 722.6 in my S600 a couple years ago.
The conductor plate in the 722.6 is not a theft relevant part, so it doesn’t need to be programmed, unlike later MB transmissions. If you can’t DIY, then at least have the shop put a conductor plate in.
With fresh fluid, a filter, and a new conductor plate, see what that gets you.
Last edited by Astro14; Sep 21, 2025 at 12:15 PM.
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Conductor plates generally go when the trans plug O-ring seal has been leaking for extended periods. If you see evidence of that, then yes by all means replace the conductor plate along with the trans plug. But if you have had a leaking trans plug O-ring then you should also check your TCU for the same fluid contamination that would kill the conductor plate.
So to amplify the signal and kill some noise:
(1) check for a leaking trans plug O-ring seal;
(2) if leaking check both the conductor plate and TCU for fluid contamination; if not leaking then ignore those two for now; and
(3) swap transmission fluid and filter and see what you get NO MATTER WHAT.
Which versions of the 722.6 found their way into which cars and what parts are in those transmissions are both perhaps mildly interesting but totally irrelevant trivia questions as far as I'm concerned. IDK why the internet loves these rabbit holes, as if you're going to rebuild your own transmission, which of course you are not.
If you need a trans rebuild you might prefer just sending yours to Sun Valley for a rebuild. But a call to Marc first will help you sort through that issue if and when you need.
GL and keep us posted.
maw
So to amplify the signal and kill some noise:
(1) check for a leaking trans plug O-ring seal;
(2) if leaking check both the conductor plate and TCU for fluid contamination; if not leaking then ignore those two for now; and
(3) swap transmission fluid and filter and see what you get NO MATTER WHAT.
Which versions of the 722.6 found their way into which cars and what parts are in those transmissions are both perhaps mildly interesting but totally irrelevant trivia questions as far as I'm concerned. IDK why the internet loves these rabbit holes, as if you're going to rebuild your own transmission, which of course you are not.
If you need a trans rebuild you might prefer just sending yours to Sun Valley for a rebuild. But a call to Marc first will help you sort through that issue if and when you need.
GL and keep us posted.
maw
Last edited by maw1124; Sep 21, 2025 at 12:25 PM.
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From: Nyc
S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
Yes, you're right, its the nag1 im talking about. The nag1 is good for 425-500ft.lbs of torque. The s600 transmission is good for 737ft.lbs of torque.
The car drives perfect when the oil is cool but once it overheats the car will feel like im in neutral. The car stops moving and I have to turn the car off for about 10 minutes to move the car another block or two. Then I have to shut it off again and wait for the fluid to cool down.
The mechanic did say he saw some fluid on the connector. I gave him the conductor plate, plug, filter, and seal. Ill ask him to change out the fluid and see how that goes. Thanks for the info
The car drives perfect when the oil is cool but once it overheats the car will feel like im in neutral. The car stops moving and I have to turn the car off for about 10 minutes to move the car another block or two. Then I have to shut it off again and wait for the fluid to cool down.
The mechanic did say he saw some fluid on the connector. I gave him the conductor plate, plug, filter, and seal. Ill ask him to change out the fluid and see how that goes. Thanks for the info
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Also check the TCU... they're getting scarce but at least MKUltra sells tuned replacements fairly cheaply and they are definitely worthwhile.
https://mkultraelectronics.com/product/2004-2007-v12-s65-amg/
GL
maw
https://mkultraelectronics.com/product/2004-2007-v12-s65-amg/
GL
maw
Last edited by maw1124; Sep 21, 2025 at 12:42 PM.
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From: Virginia Beach
2005 S600 2005 SL600
Yeah, the first thing I would check would be that 13 pin connector, and whether or not fluid has wicked its way up into the TCU. I guess I assumed that a competent transmission shop would’ve already done that. But then, competent and transmission shop aren’t really words that I typically use together.
It’s an easy check. Easy to replace that plug.
While that plug is actually part of the conductor plate, the conductor plates simply fail with age, it’s not related to the failure of that plug, which is simply an O-ring that begins to leak.
in my case, I had a harsh one – two shift. New conductor plate cleared it right up. I never had a leaking 13 pin connector, I replaced it when I first got the car and I replaced it again five years later as preventive maintenance. I’ve replaced it on the SL 600 as well
It’s an easy check. Easy to replace that plug.
While that plug is actually part of the conductor plate, the conductor plates simply fail with age, it’s not related to the failure of that plug, which is simply an O-ring that begins to leak.
in my case, I had a harsh one – two shift. New conductor plate cleared it right up. I never had a leaking 13 pin connector, I replaced it when I first got the car and I replaced it again five years later as preventive maintenance. I’ve replaced it on the SL 600 as well
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S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
My cars at the mechanic not transmission shop. I'll ask the mechanic to change those parts out and see if that helps.
Is that tuned tcu really only $250? Do I have to send them my tcu or is it bought out right for $250? That's really cheap. I might just buy it for the tune.
Is that tuned tcu really only $250? Do I have to send them my tcu or is it bought out right for $250? That's really cheap. I might just buy it for the tune.
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
I'm running a tuned TCU. It's better than stock, but only just $250 worth (for an S). I consider them good stock replacements. I run my car in M mode exclusively, so the benefit is just slightly faster, firmer shifts since I always control the shift points.
Now if I was in a CLK, E, CLS or even an SL I might view them differently. But hoon mode isn't something I'm into in a Sonderklasse.
maw
Last edited by maw1124; Sep 21, 2025 at 03:10 PM.
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
First thing I would do is to pull the TCU from the right SAM, open it and thoroughly clean it with contact cleaner or brake fluid cleaner. Reinstall, and see what happens.
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S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
Maw1124, what's the difference between speed shift plus+, stage 1, and stage 2 track/race firm shift wot?
Whats 150% sga for the valve body?
I'm about to order one of these tcu's but i dont want something that feels twitchy under normal driving. Anything durring wot I dont mind.
I'm not sure which one is the tcu. Under the hood I know the engine ecu is on the passenger side inside the fuse box. I cant remember if there is another ecu on the passenger side. I know there are 2 ecu's inside the driver's side fuse box but they both look the same. Which one is the tcu or are they both sams? Which one if the front sam and rear sam?
Whats 150% sga for the valve body?
I'm about to order one of these tcu's but i dont want something that feels twitchy under normal driving. Anything durring wot I dont mind.
I'm not sure which one is the tcu. Under the hood I know the engine ecu is on the passenger side inside the fuse box. I cant remember if there is another ecu on the passenger side. I know there are 2 ecu's inside the driver's side fuse box but they both look the same. Which one is the tcu or are they both sams? Which one if the front sam and rear sam?
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
On US cars, the TCU is a black plastic box about the same size and shape of a pack of cigarettes, which is just tucked inside the right SAM box on the end of a small wire harness. Remember that left/right are ALWAYS as seen be the seated driver.
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
You are standing in front of the car.
The RIGHT headlamp is on your left. The RIGHT SAM is on your left.
It is a great deal simpler if you can just ALWAYS visualize right and left as if you were sitting in the driver's seat. Then the right headlamp is always on the right side of the car whether you are standing behind the car, in front of the car, or lying under it.
The RIGHT headlamp is on your left. The RIGHT SAM is on your left.
It is a great deal simpler if you can just ALWAYS visualize right and left as if you were sitting in the driver's seat. Then the right headlamp is always on the right side of the car whether you are standing behind the car, in front of the car, or lying under it.
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From: Nyc
S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
Ok, so on the left side there's are two ecu's. Are they both sams? Which sam are the headlights connected to? Im guessing the tcu would be inside the right fuse box? I can't check since my car is at the shop 30 minutes from my house. Thanks for blessing me with knowledge. I really appreciate this stuff
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S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
I found more info on the 722.6 transmission. So the model of transmissions range from 722.600-722.699. Out of the 99 models only 722.648 and 722.649 are capable of handling 900nm (664ft•lbs) of torque. Everything else is 300 N⋅m (221 lb⋅ft), 330 N⋅m (243 lb⋅ft), 380 N⋅m (280 lb⋅ft), 400 N⋅m (295 lb⋅ft), or 580 N⋅m (428 lb⋅ft)
huge difference in torque handling capabilities. I had no idea there were 99 versions of this transmission. I'll post the link below if anyone wants to check it out
https://sportlichleicht.com/info/transmissions/722_6
huge difference in torque handling capabilities. I had no idea there were 99 versions of this transmission. I'll post the link below if anyone wants to check it out
https://sportlichleicht.com/info/transmissions/722_6
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
The common descriptor for the large sealed (removable covers) black plastic boxes are the rear corners of the engine room is Signal Acquisition Module (SAM). The SAMs contain fuses, relays, and electronic modules.
The headlight connections depend upon the headlight configuration in your car. If you have the common incandescent headlights, the high and low beams are switched. If i remember correctly, on the high beams, the left light is powered by the left SAM, the right light is powered by the right SAM. On the low beams, the left light is powered by the right SAM, and the right light is powered by the left SAM. The "...is powered by..." is because many of the exterior lights, including the headlights don't have "fuses". Each filament is powered by a separately-monitored computer-driven circuit. If the power draw for that filament is higher of lower than the programmed value, the computer cuts off that circuit, then checks it often to see if the draw is correct.
The headlight connections depend upon the headlight configuration in your car. If you have the common incandescent headlights, the high and low beams are switched. If i remember correctly, on the high beams, the left light is powered by the left SAM, the right light is powered by the right SAM. On the low beams, the left light is powered by the right SAM, and the right light is powered by the left SAM. The "...is powered by..." is because many of the exterior lights, including the headlights don't have "fuses". Each filament is powered by a separately-monitored computer-driven circuit. If the power draw for that filament is higher of lower than the programmed value, the computer cuts off that circuit, then checks it often to see if the draw is correct.
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Maw1124, what's the difference between speed shift plus+, stage 1, and stage 2 track/race firm shift wot?
Whats 150% sga for the valve body?
I'm about to order one of these tcu's but i dont want something that feels twitchy under normal driving. Anything durring wot I dont mind.
Whats 150% sga for the valve body?
I'm about to order one of these tcu's but i dont want something that feels twitchy under normal driving. Anything durring wot I dont mind.
I stuck with Stage 1, which is basically stock with faster firmer shifts. Feels like between 25% and 50% but I’m not driving it very hard.
maw
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Joined: Apr 2009
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
I found more info on the 722.6 transmission. So the model of transmissions range from 722.600-722.699. Out of the 99 models only 722.648 and 722.649 are capable of handling 900nm (664ft•lbs) of torque. Everything else is 300 N⋅m (221 lb⋅ft), 330 N⋅m (243 lb⋅ft), 380 N⋅m (280 lb⋅ft), 400 N⋅m (295 lb⋅ft), or 580 N⋅m (428 lb⋅ft)
huge difference in torque handling capabilities. I had no idea there were 99 versions of this transmission. I'll post the link below if anyone wants to check it out
https://sportlichleicht.com/info/transmissions/722_6
huge difference in torque handling capabilities. I had no idea there were 99 versions of this transmission. I'll post the link below if anyone wants to check it out
https://sportlichleicht.com/info/transmissions/722_6
maw
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Member
Joined: Dec 2021
Posts: 179
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From: Nyc
S-600 w220, Nissan s13 coupe, and Nissan s13 convertible
The w222 s65 and s600 came with the 7 speed. Is it possible to swap in the 7 speed? I was looking at the 1/4 mile times between the w220 and w222. The w222 is 1 second faster in the 1/4 mile. Im assuming most if that second is due to the 7 speed.
Also I found out what the sga is, its the valve body. I've read some nightmares after installing 150% valve bodies. I dont know if its because of the tuning or the guy got a faulty valve body but I dont think I wanna risk it yet, not until I get my 92 240sx back up and running.
Also I found out what the sga is, its the valve body. I've read some nightmares after installing 150% valve bodies. I dont know if its because of the tuning or the guy got a faulty valve body but I dont think I wanna risk it yet, not until I get my 92 240sx back up and running.
Last edited by Hank Houston; Sep 27, 2025 at 08:49 PM.
