M mode dropped to C mode on Track
Was at Wakefield yesterday, first time with the Evo rear rotors and Titanium shims. It was 38c so not that pleasant .I was wondering if any
of you have experienced the auto going to Comfort from Manual which happened every run after a few hot laps M could not be selected until approx 30 minutes after coming in. Mercedes are checking around to see
what is the cause, I would imagine it is a heat issue with the sensor and computer. Received call from Mercedes as I was typing this post, they want the car for 1/2 a day so can find the cause.
Thanks
Ian Shuttle
Last edited by shuttie; Jan 26, 2011 at 07:05 PM. Reason: spelling
Was at Wakefield yesterday, first time with the Evo rear rotors and Titanium shims. It was 38c so not that pleasant .I was wondering if any
of you have experienced the auto going to Comfort from Manual which happened every run after a few hot laps M could not be selected until approx 30 minutes after coming in. Mercedes are checking around to see
what is the cause, I would imagine it is a heat issue with the sensor and computer. Received call from Mercedes as I was typing this post, they want the car for 1/2 a day so can find the cause.
Thanks
Ian Shuttle
I'm sure your dealer will come back to you and say the trans was overheating and protecting itself from damage.
Keep us posted please.
It keeps you there until the temp drops to 130c.
Make sure your AC is off, the car runs cooler that way.
Yes, it's happened to me, busted into C looking around and wondering, "WHAT THE .... Oh."
Other times it was just that hot on the track 38+, happens more easily in M.
Don't let the dealer have your car to test that out!
It keeps you there until the temp drops to 130c.
Make sure your AC is off, the car runs cooler that way.
Yes, it's happened to me, busted into C looking around and wondering, "WHAT THE .... Oh."
Other times it was just that hot on the track 38+, happens more easily in M.
Don't let the dealer have your car to test that out!

"You oil temp doesn't seem out of line. the oil has to run over 100C to prevent any moisture from building up. On a race track outing somewhere close to 150C (300F) is possible. 175C (350F) it's time back off!!! The flash point of the oil is 224C (435F). You definitely don't want to go there even though the manufacturers claim protection to 400F !! The oil won't last too long at those temps. A non synthetic oil is done at 350F, it starts smoking."
I think you're right about the 135C/275F point being the cars preset limiter throwing it into limp mode to protect the motor. Knowing that and with the above quote just confirms again how conservative AMG is with their calculations and limits...once again, favoring reliability over all out performance. That's the reason these cars will easily run 200k miles in stock form.
This has to be a temperature modified 'protection' feature for the transmission imho since when it happened to me, the engine oil temp as I mentioned was fine. What I believe is happening at least in my experience is that in 'M' mode on the track, I am staying at much high revs in lower/middle gears than you would normally see on the street. This is leading to much higher temps than the transmission ECU would normally be seeing, as the transmission is not being allowed, (deliberately), to change up. Doubt there's any way to correct this other than installing a larger than OEM transmission oil cooler.
My second and subsequent runs I stayed in 'S' mode, and never had any issues, even when the revs were staying up much higher than you would see in 'C' mode. I hated not being comfortable staying in 'M' though.
Any other thoughts?
Bish
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This has to be a temperature modified 'protection' feature for the transmission imho since when it happened to me, the engine oil temp as I mentioned was fine. What I believe is happening at least in my experience is that in 'M' mode on the track, I am staying at much high revs in lower/middle gears than you would normally see on the street. This is leading to much higher temps than the transmission ECU would normally be seeing, as the transmission is not being allowed, (deliberately), to change up. Doubt there's any way to correct this other than installing a larger than OEM transmission oil cooler.
My second and subsequent runs I stayed in 'S' mode, and never had any issues, even when the revs were staying up much higher than you would see in 'C' mode. I hated not being comfortable staying in 'M' though.
Any other thoughts?
Bish
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Bish
I'm sure your dealer will come back to you and say the trans was overheating and protecting itself from damage.
Keep us posted please.
Thanks for the replies, Will know more on the 9th Feb, I didnt check the
engine oil temp though would have been high, I dont mind the car protecting itself though can be very distracting on the track.
I will be pushing for a higher grade oil for the motor and transmission or bigger cooler as most of my track days are on a tight track and never go over 4th gear. Maybe the computer can be programmed up, though Benz
are more than likely not willing ,though no harm in trying

Will let you know their reply.
Regards
Ian Shuttle






