Mercedes-Benz Forum banner

1 - 16 of 16 Posts

·
Registered
2012 E350 CDI & 2017 C300 Cabrio
Joined
·
86 Posts
Discussion Starter #1
I had the tranny serviced in October. (91K miles) We've been having some cold weather in the 10-25* ranges. When cold, the tranny feels like the converter is not locking up, and the engine is revving higher than it needs to. (ie: not taking advantage of the torque) It's not slipping and grabbing a gear hard, just feels more similar to a high(er) reving engine going thru the gears until it warms up. Once the engine is warm, everything is smooth sailing. I am thinking that there is a potential that the tranny fluid may be low and when cold it's not building the appropriate pressure and causing the situation? Or, maybe it's just normal due to the frigid temps and the necessary time to warm up the tranny fluid. No messages or codes, but since I can't physically check my tranny fluid, I'm not sure. Is the what other E320 owners experience in the cold?
 

·
Registered
2012 E350 CDI & 2017 C300 Cabrio
Joined
·
86 Posts
Discussion Starter #3
Just as it was designed.

Electronics holds gears longer to facilitate engine warmup.
Thanks for the input! It seems like when the tranny is cold, the tach will read 2200 rpm at 30 mph, and when it's warm it will read 1800 at 30 mph. I'll have to be more aware, as your analysis is probably correct and it's actually taching and mphing higher.
 

·
Registered
2008 ML320CDI Iridium Silver/Black, NAV, P2 pkg, Sirius, Harmon Kardon. Active Bi-Xenon
Joined
·
478 Posts
I find the 722.6 transmission in our CDI's as clunky as the one in my 1997 E300d. I really thought there would have been some improvement since 1997. The abruptness, lagging upshifts, delayed engagement from R to D on the first start off of the day.. That being said, I am sure the 722.9 (seven speed) is an improvement.
 

·
Registered
222.132 & 221.122 & 213.050 & 906.633
Joined
·
10,426 Posts
I find the 722.6 transmission in our CDI's as clunky as the one in my 1997 E300d. I really thought there would have been some improvement since 1997. The abruptness, lagging upshifts, delayed engagement from R to D on the first start off of the day.. That being said, I am sure the 722.9 (seven speed) is an improvement.
If you had not serviced your 1997 car, it would not shift well. If the 722.6 transmission is in good shape, it would shift smoothly at normal traffic and more quickly at full throttle (just like you would hope). I would say the 5-speed tranny behaves equally well as the 7G-tronic, assuming both are properly serviced (glycol leaks may have destroyed the 722.6).

Note that the tranny would need more maintenance than initially announced in the maintenance booklet of early 722.6 cars.
 

·
Registered
222.132 & 221.122 & 213.050 & 906.633
Joined
·
10,426 Posts
The TC lock-up might need some adaptation. Mine shifts too early if i apply gas lightly in early morning. I am on S mode.
I've seen several owners reporting the tranny performance improving a lot after the valve controlling the torque converter lockup has been changed (some parts cleaning and oil change at the same time). No personal experience with this.
 

·
Registered
2006 E320 CDI, 2009 ML320 Bluetec, 2009 GL320 Bluetec
Joined
·
1,476 Posts
How to make these transmission last and shift properly: Regular (Full flush 14 liter) fluid and filter changes...Repeat to keep those wear metals below 100ppm!

Knock on wood but so far for us the 5 speed has been rock solid. Wear rates thus far show fluid changes to be required every 30K conservatively.

On every change I flush the entire transmission (sump, and cooling circuit which also flushes the torque converter). My first flush was done at 30K due to the wear metals reaching 100ppm. Flushed and dropped them to around 25. Right now projected out they are going to be back at 100ppm around 35-40K post flush.

I bring this up because the people that seem to have issues with any transmission always seem to have a history of neglect in respect to the transmission fluid. If you were to look at the ISO cleanliness for these fluids, then analyze your fluid you would jump out of your skin if you let these go beyond 30K!

Read the attached pdf, lots of good information in there about hydraulic fluid cleanliness for hydraulic systems such as a transmission.
 

Attachments

·
Registered
'04 Sprinter 318 CDI, '06 E320 CDI
Joined
·
117 Posts
I find the 722.6 transmission in our CDI's as clunky as the one in my 1997 E300d. I really thought there would have been some improvement since 1997. The abruptness, lagging upshifts, delayed engagement from R to D on the first start off of the day.. That being said, I am sure the 722.9 (seven speed) is an improvement.

I just had a 2011 C Class loaner from the dealer, with the 7 Spd, and the upshifting was very harsh....nothing like the 5 spd I have!
 

·
Registered
222.132 & 221.122 & 213.050 & 906.633
Joined
·
10,426 Posts
I just had a 2011 C Class loaner from the dealer, with the 7 Spd, and the upshifting was very harsh....nothing like the 5 spd I have!
Your intention was to report that your tranny behaves at it should but you have driven another car (with another transmission) that was faulty? From above one might get the misleading impression that one of the two would typically shift poorly (should not be the case for either of the two).
 

·
Registered
'04 Sprinter 318 CDI, '06 E320 CDI
Joined
·
117 Posts
Your intention was to report that your tranny behaves at it should but you have driven another car (with another transmission) that was faulty? From above one might get the misleading impression that one of the two would typically shift poorly (should not be the case for either of the two).
I never implied faulty on either trans type, but rather observing that in my opinion, the 7 spd is not smoother than the 5 spd for upshifting. It could very well be the design of it, but I was not implying any flaw per-se.
 

·
Registered
222.132 & 221.122 & 213.050 & 906.633
Joined
·
10,426 Posts
I never implied faulty on either trans type, but rather observing that in my opinion, the 7 spd is not smoother than the 5 spd for upshifting. It could very well be the design of it, but I was not implying any flaw per-se.
Very good then. At your previous message you mentioned "upshifting was very harsh....nothing like the 5 spd I have" where I just wanted to emphasise that the 7G-Tronic should not behave like that unless it has a fault.
 

·
Registered
'04 Sprinter 318 CDI, '06 E320 CDI
Joined
·
117 Posts
Very good then. At your previous message you mentioned "upshifting was very harsh....nothing like the 5 spd I have" where I just wanted to emphasise that the 7G-Tronic should not behave like that unless it has a fault.

Harsher in comparison is perhaps a better choice of words....
 

·
Banned
2006 E320 CDI
Joined
·
932 Posts
How to make these transmission last and shift properly: Regular (Full flush 14 liter) fluid and filter changes...Repeat to keep those wear metals below 100ppm!

Knock on wood but so far for us the 5 speed has been rock solid. Wear rates thus far show fluid changes to be required every 30K conservatively.

On every change I flush the entire transmission (sump, and cooling circuit which also flushes the torque converter). My first flush was done at 30K due to the wear metals reaching 100ppm. Flushed and dropped them to around 25. Right now projected out they are going to be back at 100ppm around 35-40K post flush.

I bring this up because the people that seem to have issues with any transmission always seem to have a history of neglect in respect to the transmission fluid. If you were to look at the ISO cleanliness for these fluids, then analyze your fluid you would jump out of your skin if you let these go beyond 30K!

Read the attached pdf, lots of good information in there about hydraulic fluid cleanliness for hydraulic systems such as a transmission.
and always use MB approved Fluids!!!:thumbsup:
 

·
Registered
05 E320 CDI w/ 4 Zone Climate Control, Panaromic Roof, Parktronics. MB SDS equipped.
Joined
·
426 Posts
I've seen several owners reporting the tranny performance improving a lot after the valve controlling the torque converter lockup has been changed (some parts cleaning and oil change at the same time). No personal experience with this.
I think I saw a couple of posting from various of countries in Europe reporting a success after replacing the TCC PWM solenoid.
 
1 - 16 of 16 Posts
Top