desired_speeds

I've noticed recently that when I come to a stop (driving normal) the car delays in downshifting into 1st gear. Sometimes I get to a stop sign, stop, then when I start to hit the gas(or right before I hit the gas), I feel it kick back into 1st gear. It doesn't happen all the time but has been happening much more often recently. I also get a slightly firmer 1st to 2nd gear shift at times. Otherwise, the car is fine at 500mi. before 150k.

I did a soft adaptation reset (gas pedal kickdown trick) and it did not improve anything.

I first experienced this problem at a much smaller extent when I was in Arizona idling in 110 degree heat 1.5 years ago. I did a transmission service after I got back from Arizona and it had been fine until now.

Few things to note:
- The car is an 02 E55
- 17k mi since last trans service (pan drop, filter, trans connector, 4 qts MB 134 ATF replaced.)
- Trans level is perfect when I checked last night
- Fluid has turned into a gold color, but definitely not black at all.
- Engine mounts replaced at end of 2010, trans mount was recently replaced as preventative maintenance.

The only theories I have come up with so far is transmission fluid deterioration, flex discs worn, or a solenoid or speed sensor inside the transmission is faulty. I will check the flex discs tomorrow.

This member posted in 09 about his problem and I believe I'm experiencing the exact issues: https://mbworld.org/forums/mercedes-...0-722-6-a.html

Any ideas anyone? Thanks in advance!

Plutoe

Bad valve/spring in conductor plate------get a tranny scan!!

Damercedes

Had this issue lately and thought the same as the reply above but when I checked the fluid level it was just a touch low. Added what would be a coke can full and problem gone. These transmissions are SO sensitive.

Plutoe

You are correct typically reduced fluid flow within the transmission causes the majority of shift delays.

That means either low on fluid and or a transmission filter needs changing. However unlike engine oil transmission fluid is not consumed by the process and if you have full fluid(no leaks/check cables) and a recent filter change and have delayed gear change the next step in the process is to scan the transmission for faulty solenoids. Well that's what I do.

Damercedes

Agreed. I missed that he had checked and it was perfect level.

nelbur

I have this "lurching problem" in the winter when pulling away from a stop, for the first few miles. once things warm up it never happens and it doesn't happen in the summer. I would guess it has something to do with the viscosity of the ATF, but it is just a guess.

Plutoe

I would look to something other than viscosity,if you look at the specs, I believe the ATF fluid is good to -60F and therefore seriously doubt that your issue is viscosity.

PS: Lurching that could mean anything to anybody, what are you actually talking about?

nelbur

No. It couldn't mean anything to anybody. On my first stop or two the transmission does not seem to be in low until I press on the accelerator to go. The transmission then shifts down into first and lurches forward. Once it warms up it always shifts down into low before I start forward. This sounds to me like what the OP was seeing although in his case it may not remedy itself when the car warms up.

Plutoe

So in cold weather it's not downshifting when you come to a stop and ijn cold weather never downshifts from a stop untill you press the accelerator------------Is that close to your encounter!!

nelbur

Yes, but it only happens in the stops made in the first few miles of the day. When the car is warm it never happens and it never happens in the summer. It has done this for the five years or so that I have owned it. It is not something I would feel a need to fix, but it would be interesting to know why it happens. I just consider it to be an idiosyncrasy of the car.

SerbNerd

hmmm this happened to me today. Coming to a stop sign, make a stop, then go to accelerate and then the tranny shifts into firsts after I've started going in 2nd.

Today is a nice 5 degrees F...but like stated, once the car warms up, all is well again.

I've just accepted that my E430 is cranky after a cold start and should just be let to warm up with slow driving around the neighborhood.