Glyn M Ruck

Johnand, Karo et al with 722.9 transmissions.

Now that I'm running miles on & enjoying I have an observation & would like your comment. My 722.9 has the latest flash (I'm told). She is beautifully smooth - no jerks etc. When driving gently in S mode she is in a hell of a hurry to get into top gear no doubt to save fuel. This is fine on the flat but if you hit a rise in top she almost lugs the engine before kicking down. If you prod the throttle lightly to encourage a kick down, before you know it she has kicked down 2 or 3 gears and wants to take off rather than maintain speed. I find myself gearing down manually to maintain a gentle pace. All this in the 60 to 80 Km/h range. 37 to 50 miles per hour.

Any advice & would you consider this normal?

splinter

It is unlikely I’ll ever be labeled as a spokesman for what others consider to be “normal.” :)

Mom’s ’07 W203 722.9/M272 (2.5 litre) powertrain consistently hunts for the ‘correct’ gear during light-load suburban driving, even when subjected to gentle and deliberate throttle inputs.
Its prompt EPA- and EU-dictated consumption upshift programming is smooth as butter, although it’s actually quite annoying during practical day-to-day operation.

I typically manually select 3rd or 4th -in S mode- when initially driving off, and then permit the other available ratios only when up to highway cruising speeds.
It may be an automatic, but Touch Shift gets worked early and often on each drive cycle.

jogger

have you tried same route in C for a few days?

brbhan

Quote: "Now that I'm running miles on & enjoying I have an observation & would like your comment. My 722.9 has the latest flash (I'm told). She is beautifully smooth - no jerks etc. When driving gently in S mode she is in a hell of a hurry to get into top gear no doubt to save fuel. This is fine on the flat but if you hit a rise in top she almost lugs the engine before kicking down. If you prod the throttle lightly to encourage a kick down, before you know it she has kicked down 2 or 3 gears and wants to take off rather than maintain speed. I find myself gearing down manually to maintain a gentle pace. All this in the 60 to 80 Km/h range. 37 to 50 miles per hour."

Glyn: I am 1. no engineer and 2. basing opinion on observation of 722.6 and behaviour of my 1987 126 (SDL) still going strong.

A: Driving modes C and S are no different after about 40 mph. Shifting difference of the two modes is only up front; basically when taking off from stationery. All automatic transm. are 'Accelerator-pedal' sensitive. Put excessive (as dreamed up by the manufacturer) pressure and the trans gets the message that you need more power. So, it shifts down. As the right foot relaxes pressure the transm. shifts to suit the torque it perceives, is being requested of it.

B. Mercedes transm. is extremely sensitive to fluid level. Levelling it to read in-between Max/Min marks is insufficient. Must be dead on to shift smoothly - for those who insist on perfection . Also, whereas hot as well as cold readings are stipulated in the owner's manual, shop manuals insist on '80 F' temperature for a reliable reading. Shop manuals go as far as discrediting the 'cold' reading! In equipping dealers, Mercedes provides a proprietary temp reader for the purpose. I have found dealer shop mechanics considering this as a dispensible procedure. Generally, unless specifically requested, the mechanic tops off the way he creams his morning coffee - the rule of approximation.

The 'Sealed Transmission' concept is BS; like horse-s. found prentifully in Kruger NP. The little red plastic lock you see on the transm. filler tube plug (under the hood) is meant to lock out the owners' little fingers out of the (money) pot. If the 722.9 is sans dipstick, you can purchase a "tool" at the dealers. Yes, it is called a tool. Dealer can also provide a spec sheet they use to check the fluid level. In the absence of a leak, occasional checks - esp. after fluid change/trans-service, should suffice. but check it when eng. is at normal operating temp. Assumption is that transm is at same temperature.

Another thing to watch for: Whereas fluid change was specified at 39Kmi (on 722.6), the requirements were upped to 60Kmi. Don't believe it. Have it changed at 30Kmi. I believe, once the damage is done there is no going back. Transm. pan bolts continue to look pretty but CANNOT be re-used.

Not trusting the dealers I have done complete service myself - going by the Shop Manual. Was surprised at the amount of crap stuck to the magnet inside. I am not gentle with my cars; 'drive a Merecedes like it was stolen' they say. Works for me.

BTW:
a) I should be in Cape Town March 31, 2012. Drop me a line brbhan@gmail.com
b) Tranny fluid with MB logo is expensive. Without logo and meeting same specs it is about 1/3 that price in the US.

samaritrey

Go drive a car with the 8 speeds lol the ones i have are always hunting. This is why I like the 5 speed just enough gears for me

brbhan

'sthat a 1947-1953 MG Magnette - which is what the 4-seater was called?

Carsy

Glyn,

I think that if you are anything like me , after a little time you will become used to the way the 7 speed operates & you will drive it accordingly.

I found this to be the case with my 5 speed, now I actually know when every gear change will take place & use the throttle to stop any flaring or rough changes.

I have a friend who has just bought a V6 diesel MB with the 7 speed & he complains that it is forever changing gear . I am sure he will become used to it.

lkfoster

The picture would be of a MG TF, the headlights were flared into the front fenders.

Magnettes, at least the post-war ones, were the MG four door sedans. The mother-in-law has a '58 ZB Magnette. Nice car but not a Jag. Hers will be even nicer when I get around to un-jamming a stuck rear brake shoe.

Glyn M Ruck

Thanks splinter - your findings are the same as mine & your reaction similar. Benz says the transmission behaves better with higher torque engines in the range. I'm not so sure. I know it is a bit of a pain with the 4 cyl petrol engines. I even find that with the touch shift I have to be careful or it changes down multiple ratios instead of one as the 722.6 does. They could have programmed multiple ratio downshifts with the kick-down or modulator circuit but single range changes with the touch shift per tap. It feels like optimal programming "in progress/process" but not quite there yet.

Glyn M Ruck

Thanks for the input: Technically I know the 722.9 intimately. I've even done some training on it to Benz staff in Asia. I have just never lived with one personally. I'm an oil man & was involved with the 236.14 fluid development.

All non AMG flash Boxes with S & C pull away in 1st in S mode & 2nd in C or comfort mode (old winter mode on early 722 series 5 speeds)

From the 722.9 technical training manual:

S (Sport) first gear start
C (Comfort) or E (Economy) second gear start, earlier upshifts and later down shifts. Auto default to E on Blue Efficiency models.

Note: Transmission will start in first gear if any of the following apply.
1st gear manually selected.
3/4 to full throttle applied from stationery start.
Engine cold (catalytic converter warm up)

Now - to precis the following: Certain high torque diesel models will pull away in first gear in both modes to protect the torque converter.

You are spot on that the change interval s/b EVERY 60,000Km or 39K miles with filter. I'm certainly aware of the stretch bolts on the pan, the new design pan & spill tube. See my posts with pics on the 209 forum & Johnand's superb thread on DIY maintenance.

Yes they are level sensitive. 0.2 of a litre one way or the other can effect performance.

Previously when I have driven 722.9 transmissions I have always driven the cars harder & then they behave better. Now I'm running in normal traffic.

Glyn M Ruck

No - I've only had the car since Friday. That's next on the list

Yes - Lexus 8 speed PIA

Indeed JC. I knew my 5 speed backwards & could predict its every change. A far more settled box - even so manual change should be done at constant throttle on the 722.6, up or down the ratios - trying to predict it usually leaves gasoline models with retarded timing at the change point & you trying to back off slightly which messes up the change. That said - Johnand and I have discussed on a number of occasions that you need to drive the 7 speed very precisely & deliberately & you will get on together a lot better. Clumsy throttle inputs & yo-yoing the throttle as many do will leave it confused.


I appreciate all the input.

johnand

Glyn,

As we have discussed before, the 722.9 takes some MAJOR retraining on the way you drive. There is an extremely fine line between a single gear downshift to maintain speed on grades vs. all hell breaking loose and the transmission kicking down to the lowest gear. I find that typical of S mode, and less so on C mode. I find I am using C mode much more lately as it is easier to modulate the transmission operation.

Since I have been through many flashes, on the 722.9, I can say that phenomenom got worse in later flashes, but was worth it for the other improvements.

I am still surprised you are seeing this so much in your E35 M272. The few E35 M272 and 722.9 equipped cars rarely seemed to have this same issue like my E25 M272. Is it normal? I am afraid so. Like Trey pointed out all these new very high gear count transmissions and increasing pressure for higher fuel mileage have made this type of programming the norm. Yes, the Lexus 8 speed is horrible compared to the 722.9. Hell, the 6 speed in my VW Tiguan (Aisin-AW) is even much worse than the 722.9. It is CONSTANTLY lugging and needs to have the go pedal hammered. Then the turbo kicks in and the trans shifts to the lowest gear possible

LILBENZ230

I've been saying this all along but everyone thought I was just a hater. The 7G has too many gears and shifts too much, especially with the small 2.5L V6. With EPA ratings of 19/25 down from 23/32 for the 722.6 C230K, what was the point of so many gears? They can't seriously say it was fuel economy driven when that took a significant hit.

tommy

Marketing is a b1tch.

Glyn M Ruck

Did my first run today in typical traffic & on my typical routes in C mode. Now that is a hell of a lot better for my town driving. I can live very well with "Comfort" behaviour. My 722.6 was never taken out of S mode.

There is one tremendous benefit to the 7G. It allows the 350 to easily match my C240's fuel consumption. That is quite an achievement.

jogger

C mode it is a smooth start and drive but if you need the quick start go to S. That has been my experience.

johnand

Yep, or just tap it into 1st while in C mode.

I rarely drive in S mode anymore. I find C mode much smoother in town, and frankly other that starting out in 1st, I don't see much difference in S mode other than harder to modulate it as I explained above. The only drawback to C mode is rolling forwards or backwards on steep grades from a stop with the higher gear ratios.

johnand

You are just a hater

I think the 7G was more just to reduce manufacturing costs, by sharing the transmission across models and engines. I bet the mileage would be essentially the same with the E25 M272 behind the 722.6. What would NOT be better is the performance.

For the record, while not perfect, I still REALLY like the 722.9. Even with my E25 M272

jfelten

The 7G in my car still shifts a bit roughly for my taste even after a fluid change. The dealer told me the transmission was shifting within range, but that the shift points were all extremely high because the previous owner must have driven very aggressively. The told me my software was up to date, but they gave poor service and I have very little reason to trust anything they said.

The quirks I've noticed:

Downshift to first is very harsh when decelerating and car is cold. It usually kicks in 5-10 mph even in comfort mode, but performs much better once warmed up. Is it really necessary to shift into first when decelerating?

Shifts are buttery smooth sometimes but harsh other times. I haven't yet found a discernible pattern here. It feels perfect at times, and not that great at others.

I had a 2010 c300 loaner and the transmission on that car was much smoother than mine, but at the same time it was much less lively. My car downshifts much more eagerly, and feels a lot quicker despite having the same engine. It could be the way the transmission is adapted, software version or age of the transmission. I get the impression that how the transmission is adapted makes a huge difference.

This transmission behaves differently than any other car I've owned, and I'm getting used to it. I kind of like it, because it makes the car feel alive.

I'm just going to live with it for awhile, but will always have a nagging worry that I have one of those transmissions with improperly installed gears.

johnand

Several things are wrong here. NO shifts should ever be harsh. Mine shifts buttery smooth under all conditions. Second, you should not be getting any downshifts to first while decelerating. That was an issue that has been corrected via valve body and/or software updates. Mine did that when new, but the last update fixed that completely. Any under no condition should it ever downshift to 1st in C mode.

Yes, when cold the shifts are slightly more pronounced and happen at higher RPM, which is normal to help heat the catalyst quicker. But, they still should not be harsh.

Have you done the fluid and filter change at the recommended 39K miles?

I would get another dealer to update the software, or insist your dealer take another look. The fact that you are getting downshifts into 1st on deceleration, means you DO NOT have the latest software. The latest software will only downshift into 1st on deceleration once the car comes to a COMPLETE stop.

Since you are in Seattle, we should meet up sometime, and I can reset the adaptations for you with STAR and see if that helps.

jfelten

Thanks for the kind offer to help with my transmission.

I just had the fluid changed last week. I had a thread about taking it back to the dealer to redo it because they didn't drain the torque converter, so I'm not likely to ever go back there. The fluid changed helped, but it still seems too harsh.

Another dealer I talked to wanted a couple hours to diagnose and then extra time to readapt and update the transmission. It would probably end up being $500 or so, which would is too much. Also an indy mechanic didn't seem to able or willing to do the software upgrade. Maybe I'm just not talking to the right people.

My plan is to create my own DAS machine, and investigate doing the software update myself. I found a group of British hackers that have a DAS machine image and I was going to try that out on VMWare. I'm a bit worried that I could brick the car electronics.

A valve body fix would be around $1200 if I had somebody else do it, so I'm not too eager to find out that's the issue. So I'm just living with it for now. The transmission shifts acceptably, but I know it is not quite right.

Hope I'm not hijacking this thread.

Glyn M Ruck

John is spot on as usual! The change down to first on deceleration is a dead giveaway that you don't have the latest software flash. The car should come to rest & then select first - ready for takeoff. I use this as my "software version measure" when helping friends on their cars.

You are not hijacking the thread. That's what it's here for. To discuss 722.9 behaviour & correct what can be corrected at this time on this ever evolving transmission. That is the pleasure of the fully electronically controlled auto as opposed to old hydraulic, speed & vacuum controlled boxes.

EDIT: Also remember that a transmission that gives better performance will always give you a fuel saving if you choose not to make use of the performance gain.

johnand

That's right, I remember your posts about them not draining your torque converter

Not trying to be negative Nelly, but good luck building a knockoff STAR system that can do online SCN coding. That is what is needed to update the TCU software. I have yet to see anyone successfully pull it off. The only way I know of to do SCN coding with a STAR system is buck up and pay the $25,000 MB wants for a genuine STAR system.

jfelten

Ah that would explain why the indy mechanic couldn't do it.

I like challenges, and I'll look into it more. Do you know if the software updates are available online anywhere. I remember reading that for $20, they would give you access to their software updates/documentation database for a day.

johnand

The $20/day you are talking about is for Startek info. It has repair data, TSB, etc.

The STAR and DAS stuff is an entirely different animal. Software is not available legally except to genuine STAR system owners that have a current subscription $$$$$$$$$. There are many good sites that have download links to the software and instructions on how to install. With that software and a multiplexer clone, you can have a mostly fully functioning STAR system that will even download current software updates from MB But, beware, if you allow updates, you will at some point in time find that your multiplexer no longer works. MB periodically looks for clone multiplexers on their network, and blacklists them. There are ways to un-blacklist the multiplexer. Just look on the same sites that have the sofware and instuctions. Bottom line a clone system works almost as good as the real thing, at a cost ~$500, but it does require some work to keep it updated and working and is illegal. Also, as I said earlier, no online SCN coding, which is required for quite a few things. But, I suspect that nut will be cracked at some point in time. Just some things to consider.