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My car is acting kind of funny. It stays in gear without shifting until I have been driving the car for a while. It only does it when the car is cold, but once I've been driving for a while it starts shifting normally. Could this be because of the drop in temperature? My car just turned 60K miles and I know a service is due, but would that cause my tranny to start acting up?
 

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Alright, I do not own a high-performance E55, but I'll take a stab at it.

The catalytic...


Alright, I do not own a high-performance E55, but I'll take a stab at it.

The catalytic convertors are not warmed up yet. In the morning, especially when it is cold, the car will have delayed shifting. That is completely normal. I believe this delayed shifting technique is used to heat up the EGT's so the cats can function properly.
 

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1999 E55 AMG
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I'd agree with that guess as well. Just had my catalytic coverters changed due to deterio...

I'd agree with that guess as well. Just had my catalytic coverters changed due to deterioration. Prior to replacement, the tranny was shifting higher and more abruptly than normal until the car warmed up. Now it happens with much less frequency.

Just to be sure though, you may want to have a dealer check it out. I know that's a brave thing to do with these cars, when the simplest repair can sometimes run in the thousands.
 

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shifting weird

I have a 2000 E55. Cars are my passion. The shifting bothered me too. I researched it (MBZ technicians/mechanics). Don't panic it is normal. It is as someone else explained it. When the car is cold the heat is diverted to the cat until it reaches peak temp for optimum performance. Once it is reached the shift curves resort to normal. As long as you don't see any leaks on the driveway (Transmission fluid) I wouldn't worry about it.

V. Moreno
 

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2003, C32
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The transmission runs most efficiently when the oil
is around175F, below that value, one will get excessive wear.

The oil flows through the cooler in the radiator, to keep the trans temp in the proper range for optimum performance.

Too cold or too hot is bad for the transmission.

The shift feeling is probably programed in by MB, to improve lifetime. Also the fluid has a different viscosity, when cold.

Don
 
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