97 C280 tranny & A/C are possessed!
 

I have a 1997 C280 that I bought used about a year ago from the original owner. She had all the service records from the very first mile, all done at the dealer. Even stuff most people don't do (like having the brake fluid changed 3 times in 7 years and 98000 miles... just for maintenance!) This car could have passed for brand new.

Anyway, lately I've been having 2 specific (unrelated) problems. Well, maybe they're problems. Maybe it's normal. The first one is how the tranny shifts. I guess it's been this way since I got it but my wife drives it primarily so I never noticed it until now. When you first drive it after it's been sitting all night, the tranny seems to stay in first gear for a long time. My other car (and other cars I've had, not MB's though) will kick into 2nd gear at about 15-20 MPH. The C280 will wind itself up to 3000-4000 RPM and 20-25 MPH and hold it there unless you jump on the gas and force it to shift to 2nd. After it warms up it doesn't do it anymore.

The second problem is with the A/C unit. Mine has the climate control head that's about the size and shape of the radio with the buttons along the top and bottom and the display in the center. Sometimes when you switch between floor, vent and defrost (and the many combinations of) it won't switch. Also, sometimes if the temperature is set low and you turn it up it won't get any hotter. This is even after driving for a while and the engine is warmed up. The coolant level is fine and I just had the system flushed about 6 months ago. If you turn it off and back on again it will usually start behaving for a while, other times it starts working OK on it's own.

RE: 97 C280 tranny & A/C are possessed!
 

I'm affraid I can only comment on the transmission. I've noticed similar behavior, however mine shifts well below 20mph when cold and when warm, it eases into gears nicely.
When I've talked with mechs about this transmission, they tell me I'm fortunate to have a '99 because MB made changes in the valve body to improve it from previous years. I think you can update your transmission, but then again, mine behaves a little bit like yours so I don't know if that is you problem.
Does you wife drive the car slowly all the time? This transmission is always makeing calculations on when to shift based on how one is driveing. For example, I've noticed when I'm accelerating fast, the transmission, lets the engine rev way up before shifting. When I crusing around town, I'm in 5th gear overdrive at 35mph and rarly exceed 2K rpm before it shifts.

RE: 97 C280 tranny & A/C are possessed!
 

If I understand you correctly, you're saying the tranny has a processor that learns and adapts itself to the driving patterns of it's owner? If so, that would actually make a lot of sense in this case. She only drives it about 5 miles one-way to work, all in town (no more that 35 MPH at the most, usually between 25-35. Trust me, you do not want to be behind her in traffic if you're late getting somewhere) Everything else about the tranny seems normal to me, so maybe it's nothing to worry about. Thanks for your response!

RE: 97 C280 tranny & A/C are possessed!
 

Yep the 99 adapts to the way you drive, as it is a electonic drive by wire transmission. I have a 99 C280, and it works as Rock Solid said, I don't know if the you can update your tranny, as it might not be the drive by wire on the 99's? Also, this tranny will stay in gear a bit longer when cold, so the engine heats up faster, pollution and all that, what you describe is normal. As far as the HVAC try this little trick. diconnect the GROUND wire of the battery for 30 minutes and then reconnect. This will default the ECU back to factory settings. See how the HVAC works then. I found this out when I installed a B&B CAI and in the instruction they tell you to do this before you restart the car after the CAI is installled, so the MAS can adapt quckly to the increased air flow. Also, I was having a nagging problem with the no hold key in start postion feature. After I reset the ECU, now I just turn the key to the on position hold it a second and let go and the car starts up. before I would have to hold it until the enginer started. Even Mercedes couldn't fix this.

As rock solid said I have notice the same operations of this tranny, I usually drive around town in 4th or sport mode as Mercedes calls it. Also, there are two setting W for winter, car starts up in 2nd gear and has two reverse ration's and S Summer car start up in 1st gear. I was also told the electonics change the ratio of the the W and S settings. If you have ESP and get into deep snow, you switch if off and the differential locks up giving you power to both rear wheels.

RE: 97 C280 tranny & A/C are possessed!
 

The driver-adaptive transmission hold the higher rpm on cold engine. That is how they work. Sometimes it can be annoying. When I had my ML camping and switched transmission to low, the following morning the car would stay on the 1-st gear even at 20 MPH.
Engine braking in this situation is so powerful, that the wheels skidded on dry asphalt after taking foot of gas pedal. SCARY!

RE: 97 C280 tranny & A/C are possessed!
 

Yea most people have covered it, i wouldnt be worried if i was you.
I get a similar problem with my tranny, it wont shift unless i make it ;) :D

RE: 97 C280 tranny & A/C are possessed!
 

Thank you all so much for your information. I've never had a car like this before so naturally I'm a little apprehensive about everything I'm afraid might be wrong with it. I'm glad to see you're all so willing to help here. I haven't had such luck with other (not MB related) message boards I've visited in the past. Usually they're too busy posting pictures of their car stereos or trash talking every newbie who comes around. Thanks again!

:)

RE: 97 C280 tranny & A/C are possessed!
 

Wizard,
Do you recommend selecting 4th as the highest gear for around town rather than 5th or overdrive? I've been told that 5th gear is the weakest gear in the transmission and that one should only use it above 40mph. (Though the transmission will shift into 5th, if its not in sport mode, below 40mph)
I don't want to save a few pennies on gas while I'm wasting 5th gear.[sm=smiley25.gif]

RE: 97 C280 tranny & A/C are possessed!
 

hey your a newbie[:-], bugger off and do a search instead of asking stupid questions that have already been covered! bloody hell, what type of stereo u got, if its not big and powerful bugger off!
feel more at home now :D:D haha ;) jks

RE: 97 C280 tranny & A/C are possessed!
 

When I tow my 5000+lb boat with trailer using our ML 320, it stays on the 5-th over 50 % of the time. It only switches to 4-th on heavy wind, or grades.
The difference between 4-th and 5-th is only 500 rpm (when 3-th to 4-th is about 2500), so not a big deal this way, or another