Has anyone ever used Lubegard transmission additive for the C63 7mct cold start slip
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Joined: Dec 2025
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w204 c63
Has anyone ever used Lubegard transmission additive for the C63 7mct cold start slip
Recently, the weather has turned cold. I found that when the 7mct was cold-started and shifted to D gear, the engine speed rose when I stepped on the accelerator, but it didn't move. Then there was a "bang" sound, as if the clutch was engaged, and it started to move. I thought my car was broken, but when I checked on the forum,
I found that this was a common problem. I discovered an additive that is very popular on the bitog forum. That is Lubegard red, an additive used in AT models, which can solve problems such as gear shifting jerks and slippage.
However, although the 7mct is an AT transmission, it doesn't have a hydraulic torque converter. Instead, it has a clutch plate set. I sent an email to lubegard, who replied that my 722.9 could be used. But I seriously suspect that they don't know that the 722.9 in amg models is an mct rather than a hydraulic torque converter. ：nix：
So I would like to ask if there are any partners on the forum who have used lubegard products. I hope you can share your experience of using them. Thank you very much
I found that this was a common problem. I discovered an additive that is very popular on the bitog forum. That is Lubegard red, an additive used in AT models, which can solve problems such as gear shifting jerks and slippage.
However, although the 7mct is an AT transmission, it doesn't have a hydraulic torque converter. Instead, it has a clutch plate set. I sent an email to lubegard, who replied that my 722.9 could be used. But I seriously suspect that they don't know that the 722.9 in amg models is an mct rather than a hydraulic torque converter. ：nix：
So I would like to ask if there are any partners on the forum who have used lubegard products. I hope you can share your experience of using them. Thank you very much
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Joined: Dec 2025
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From: Keep it simple - keep it OEM
AMG C63s Coupe
I generally don't think much of such special fluids, whether for the engine or transmission.
Check transmission for error codes & wear at an MB dealer using Xentry.
Chip tuning or frequent race starts cause increased wear.
Check Start Off Clutch Wet as example MB A2212500301 (check correct partnumber by VIN !)
Check magnetic valve transmission.
Check transmission oil level.
Think about transmission oil change with oil that have the correct MB transmission oil specificaton MB xxx.x.
Check transmission for error codes & wear at an MB dealer using Xentry.
Chip tuning or frequent race starts cause increased wear.
Check Start Off Clutch Wet as example MB A2212500301 (check correct partnumber by VIN !)
Check magnetic valve transmission.
Check transmission oil level.
Think about transmission oil change with oil that have the correct MB transmission oil specificaton MB xxx.x.
Last edited by C63s_Jack; Feb 10, 2026 at 02:58 AM.
Thread Starter
Junior Member
Joined: Dec 2025
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w204 c63
It's a great experience. This car has basically never started as a racing car and has just been maintained with MB's official 236.15 transmission fluid. Perhaps changing the Start Off Clutch can solve the problem immediately, but it will cost a lot of money after all, and I see many cyclists do this without further damage. I learned that lubegard red has a good reputation, but I haven't seen any cases of its application in 7mct, so I'd like to post a message to ask
Last edited by vasilyang; Feb 10, 2026 at 11:28 AM.
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From: San Francisco Bay Area
2019 C63CS
You need to properly diagnose this instead of trying to mask the issue with some additives. RPM flares and "bang" noise is a common result of a failing wet clutch, low/dirty fluid or faulty solenoids.
Out Of Control!!
Joined: Nov 2018
Posts: 11,463
Likes: 5,354
From: San Francisco Bay Area
2019 C63CS
It's a great experience. This car has basically never started as a racing car and has just been maintained with MB's official 236.15 transmission fluid. Perhaps changing the Start Off Clutch can solve the problem immediately, but it will cost a lot of money after all, and I see many cyclists do this without further damage. I learned that lubegard red has a good reputation, but I haven't seen any cases of its application in 7mct, so I'd like to post a message to ask
This is one of the reasons I ultimately ended up passing on the PFL back in 2018 and I almost abandoned the idea of getting a C63 until they revealed the 2019 FL with the new and much improved 9-speed MCT. The big changes they made there in addition to making it more responsive, are shorter gearing and starting off in 1st gear regardless of the driving mode. So none of that clutch slurring happens when just driving the car normally around town. The clutch always quickly engages when starting off the line w/o needing to excessively slip it. In the PFL you can help this by driving it at least in Sport mode, where it starts in 1st gear all the time.
Last edited by superswiss; Feb 10, 2026 at 01:07 PM.
Thread Starter
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w204 c63
This brings up another point in addition to my advise of getting this properly diagnosed. Not driving it like a "Race" car may have contributed to this. One of the issues with the old 7-speed MCT is that it starts off in 2nd gear when in Comfort mode. This causes excessive clutch slip when starting off. Those of us who have driven manual transmissions are well aware of how much the clutch has to be slipped when starting off in 2nd gear. The 7-speed also has relatively tall gearing, so that adds to it. I understand that AMG was doing this for comfort and hoping that being a wet clutch, the additional wear would be marginal.
This is one of the reasons I ultimately ended up passing on the PFL back in 2018 and I almost abandoned the idea of getting a C63 until they revealed the 2019 FL with the new and much improved 9-speed MCT. The big changes they made there in addition to making it more responsive, are shorter gearing and starting off in 1st gear regardless of the driving mode. So none of that clutch slurring happens when just driving the car normally around town. The clutch always quickly engages when starting off the line w/o needing to excessively slip it. In the PFL you can help this by driving it at least in Sport mode, where it starts in 1st gear all the time.
This is one of the reasons I ultimately ended up passing on the PFL back in 2018 and I almost abandoned the idea of getting a C63 until they revealed the 2019 FL with the new and much improved 9-speed MCT. The big changes they made there in addition to making it more responsive, are shorter gearing and starting off in 1st gear regardless of the driving mode. So none of that clutch slurring happens when just driving the car normally around town. The clutch always quickly engages when starting off the line w/o needing to excessively slip it. In the PFL you can help this by driving it at least in Sport mode, where it starts in 1st gear all the time.
