Reluctant First Gear?

2125 Views 16 Replies 4 Participants Last post by iwrock, Feb 27, 2007

iwrock

Discussion Starter · Feb 22, 2007

Does anyone else with the 7G tranny have a problem getting the car into first gear from a roll?

1st gear runs to 6k rpm @ about 35mph, but my car doesn't like getting into 1st from a roll. Even at 20mph I have to repeatedly click the shifter to eventually get it to downshift. It just prefers to stay in 2nd.

Off the line, it hurriedly shifts to 2nd. It's almost like the car doesn't want to rev in 1st, and is spending the LEAST amount of time in that gear.

Even holding the shifter to the left in the downshift position for like 5 seconds still leaves the tranny in 1st, unless I repeatedly keep pushing it to the left.

1 - 17 of 17 Posts

SDSilverM3

· #2 · Feb 22, 2007

I bet it's because 1st gear is probably short as hell in the 7G. I try not to go into 1st gear in my car. It's rather violent.

Exit2ek might have more insight on why it happens. He is our local resident expert.

iwrock

Discussion Starter · #3 · Feb 22, 2007

1st gear IS short, but it still runs all the way to 35mph. And from 20mph, it's definitely not going to overrev either. At 20mph it would be in the midrange, ready to pull a fast one.

jangy

· #4 · Feb 22, 2007

They had to program it to minimize TQ at the 1-2 junction. That is where all the issues have been (mostly). Check to make sure you have the most recent revision (valve body and tranny software). I had heard that the shifting is smoother, bt it could just be that it doesn't do it anymore.

iwrock

Discussion Starter · #5 · Feb 22, 2007

jangy said:
They had to program it to minimize TQ at the 1-2 junction. That is where all the issues have been (mostly). Check to make sure you have the most recent revision (valve body and tranny software). I had heard that the shifting is smoother, bt it could just be that it doesn't do it anymore.

My car is a late production, so it should have the update. It had just gotten on the lot when I picked it up. It's also very smooth on the shift, but I'm having a bitch of a time getting into the damn gear.

One MAJOR gripe since I'm at it, the trans gives a HARD ugly kick when slowing down to a stop while holding 2nd gear. It tries to rev match for some reason (even though it's already in gear) and simply has wrong timing. Shit I do better with my right foot in all the other cars.

jangy

· #6 · Feb 22, 2007

Actually, the true test to the update is to allow the car to slow down from about 20mph. If it kicks hard when shifting from 2nd to 1st (at 5-10mph), then you have the old revision.

iwrock

Discussion Starter · #7 · Feb 22, 2007

Is that when the car is in Drive, or holding any specific gear?

It's smooth when just loafing around in Drive and letting it shift as it pleases, but it kicks like a mufucka when holding 2nd gear.

jangy

· #8 · Feb 22, 2007

That is with it in drive (and sport mode). What do you mean rough shift when holding second? If you are holding, it will only shift at extremes, right?

iwrock

Discussion Starter · #9 · Feb 22, 2007

Ok take this scenario. I was playing between 1st and 3rd between cars trying to get somewhere in traffic. The light turned red, I was in 2nd gear, and i just let it slow itself down when coming to the light. I was going to leave it in 2nd until I stopped. At about 20mph the car just lurched out of nowhere, as if I threw it in 1st and jabbed the gas.

SDSilverM3

· #10 · Feb 22, 2007

My car does that too. At a certain point of going up the hill to my house it does a violent downshift. I can duplicate it every single time I go home.

iwrock

Discussion Starter · #11 · Feb 22, 2007

Ya but it doesn't follow through with it. It just jabs the gas, knocks out my eyeballs and then settles back down. ECU controlled throttle FTL!

jangy

· #12 · Feb 23, 2007

Actually, that is the tranny flash. The tranny wants to go into first, and sends a signal to the ECU that it is. That is where you get the bump. Problem is that the ECU doesn't follow through, since it normally wouldn't at that particular speed.
Going 20 and having the car downshift can be pretty violent.
I would see if I could duplicate it and have MB take a look, just to document. Tranny issues are easy pickings for a lemon law case.

iwrock

Discussion Starter · #13 · Feb 23, 2007

I don't care too much to make a big deal about it. It sucks, I hate that issue, but it's not worth my time. The car is a lease and I'm definitely not keeping it after 26 months. The only attractive part was the rate. I've never really liked any 6 cylinder cars, and this is not going to be an exception. In fact, I've already started wondering if I can trade it up for something else in a few months.

At that time, I'll be asking you what you did to give in your 2005 and get the 06.

jangy

· #14 · Feb 23, 2007

You can trade up at any time. That is not an issue at all. Let me know and I'll hook you up. Is it leased through MB Credit?

iwrock

Discussion Starter · #15 · Feb 23, 2007

jangy said:
You can trade up at any time. That is not an issue at all. Let me know and I'll hook you up. Is it leased through MB Credit?

Yes, MB Credit.

The damn salespeople at MB of Encino act like MB Financial will castrate you for early turn-in. Morons. :thumbdown:

exit2Ek

· #16 · Feb 27, 2007

the 2-1 downshifts is the biggest problem the 7 speed has. unfortunately there are several things that may cause this(as well as other harsh shifts in different gears). first thing that needs to be done is see if it has the most current software. benz is constantly updating the software so don't assume your car has it. if that doesn't fix it the valve body may have to be replaced or even on of the cirlips holding one of the on of the clutches inside the tranny. heck, maybe a tranny needs to be replaced. take it in and have it checked out. good luck buddy.....

iwrock

Discussion Starter · #17 · Feb 27, 2007

Thanks, I'm definitely going to have it looked at soon when I take it in for the initial checkup.

I think it's more of a program thing, since it does manually engage 1st when I'm persistent with it. I just want to get every last horsepower from it, since it's not all that powerful to begin with.

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