Kar don

My 550 won't engage first gear unless I come to a complete stop and count 1 second. If I don't wait for the the thump and hit it right away it lags or slams. Does anyone else's not engage first? Every other car I've had engaged first as you were slowing down almost to 0 mph... heck even the 2006 and 2007 models I drove with the 7g did that. This transmission seems to never know what gear to be in and is very jerky. I have only 4800 miles, whats going on here. Why didn't those stupid engineers just make it a 6 speed transmission if 1st wasn't going to be used in 90% of driving conditions.

amdeutsch

Doesn't make sense. As long as you are in 'S' mode it should do it.

Kar don

yup, in S mode. Doesn't engage 1st as I coast to a stop, only if I completely stop and wait for 1 second. U can feel it surge forward (slightly) as 1st engages.

amdeutsch

I'll check mine in the morning for you. I never noticed this.

Untertürkheim

The 7g is designed to do this for safety and comfort. Because 1st is geared so low, it is designed to only be used from a stop. MB has been doing things like this for a very long time.

Kar don

No it hasn't, driven several 2007 GL450s that would engage 1st while rolling to a stop... it would feel like you were getting rear ended sometimes when it would downshift. Other times it was silky smooth. I think benz did that 1st gear only after stop was to stop owner complaints of the 2 to 1 slam. I think it is just a great way to cover up the problem for MB.

All the 5 speed MBs I have had in the past went into 1st when rolling to a stop.

K-A

I think I have a similar issue. Lately when coming to a stop, it seems my Tranny starts thinking about what to do, and I usually cringe when I have to re-accelerate knowing if it does go into first it's gonna SLAM really hard, which sometimes it does.

I'm going to the Dealer tomorrow for the 3rd time about Transmission complaints, such a smooth car, but the Transmission is not butter during low speeds.

amdeutsch

Checked it this morning. Around 7,8 mph I noticed a small blip on the tach. Was smooth downshift. HTH

Kar don

thanks for checking Amdeutsch, you sure that blip was 1st gear and not 2nd gear?

amdeutsch

Didn't see another blip below that. Watched it several times. Butt dyno was of no help.

Kar don

Thanks Amdeutsch,

Anyone else have any 7g input? Konigstiger?

konigstiger

I would suggest bringing the vehicle in and have a shop foreman ride along so he can witness your claim. In addition to diagnosing the problem, suggest:

- An EDAC claim is opened with claim number included on your invoice. MBUSA will now monitor the matter if, and when future transmission work is needed.
- Check the transmission control module determining if it needs to be flashed with the latest software or valve body needs replacing.
- Flush the ATF and replace with new 722.9 ATF-4134 part #A001989680310 to remove any particles that might have accumulated and provide better performance as per S-B-00.40/89 AUG08.

NCE500

I can completely relate to how you feel, my 550 does exactly the same thing; won't engage first gear unless I come to a complete stop. It does however use 1st gear 100% of the time when starting from a stop. Like you, I thought there was something wrong with mine, but I drove another dealer car and it was exactly the same as mine back in September 07. I did however have (what was then) the latest software loaded several months ago, and can say that aside from this calibration issue, mine performs perfectly, no thump of any kind at low speeds, it just starts in 2nd from low speeds unless I use full throttle and it will kickdown to 1st after about a second. I have gotten used to it, it is not bad once one understands the logic; I just remember to come to a full stop at 4 way intersections etc. when I want a 1st gear start.

The earlier 7G cars had a lot of complaints with thumping when the trans shifted into 1st gear when decelerating at low speeds when coming up to a stop in S mode, Mercedes went through numerous software and hardware updates to fix it; I had at least two updates done to my 05 E500, it was ultimately much better but still never what I would call 100% smooth.

The current calibration with low speed 2nd gear starts completedly corrects that problem.

K-A

You said it. I've been going through the exact same thing. Went to the Dealer again yesterday and I'm starting to realize I think I'll have to live with it unless it'll do some thumping during the test drive with the Mech (never does of course). The latest Software helped mine alot and it is alot less now, but not 100% smooth like you said.

Kar don

See, NCE500... I want the old style software where it downshifts as you are decelerating like your old E500. Thats the way it should be so you always have power on demand. Say stuck in a traffic jam and you are rolling at 3-5 mph and then a hole opens up and you want to hit it, the car won't go unless you force it (full throttle or touchshift). Every other car I've owned would be in 1st gear in that situation.