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W124 jerky gearchange

Williamwoo

MB Enthusiast
Joined
Jul 8, 2010
Messages
1,072
Location
Somerset / Chives, France
Car
W124 E320 estate / Audi A6 BiTdi / Skoda Yeti 4x4 / VW Caravelle
Hi all,
Gearchanges in my E320 ('95, 4-speed) have recently become very harsh, especially upward and at lower engine speeds. The gearbox oil level is correct and the oil itself seems fine (clean and not burnt-smelling). At higher revs though, the gearchanges (particularly from 2nd to 3rd) seem to be noticeably smoother. It doesn't make much difference whether the car is hot or cold.
Any ideas anyone? Thanks in advance.
 
Is it the same box as fitted to earlier (eg W123) cars? If so, there is an adjustable parameter that controls severity of shifts. The guy here who understands exactly how it works is Allibassi.
 
When was the ATF & filter last changed?
 
http://www.w124performance.com/docs/mb/other/tranny_722_Mitchell.pdf

There are 2 elements controlling shifts-one is a cable attached to the throttle control and the other is a vacuum modulator- the vacuum system may have developed a leak or the cable needs adjusting?

My guess would be a vacuum leak as at a very high level vacuum modulater controls the shift quality and the Bowden cable does the shift points if I recall correctly.
To confirm you could disconnect the vaccum to the transmission and plug it engine side and see how that alters things.
 
Above all posts But only if the auto box is checked the right way .Can you tell other members,, and me just how you went about checking the level ?

Hi, with the car fully warmed up, I checked the level with the dipstick with the car on level ground, engine running and the car in Park. (I've always thought this was the correct way to do it, but am willing to stand corrected!)

Re the ATF and filter, they were changed about 7 years (and 30,000-ish miles) ago. I doubt it is these though as the gearchange fairly suddenly became rough, rather than deteriorating gradually.
 
William no it is the right way to do the check on your auto box.. But only wipe the dip stick with a lint free cloth .Pull it out wipe it, then put it back in and again pull it out then do the check on it ..
 
The other thing that goes wrong with these boxes are the hydraulic pistons that activate 2 out of the 3 brake bands that lock up the epicyclic gear carriers. The early 722 boxes suffered from B2 piston failure [ they were notorious for it] till they were redesigned. Normally the gear box has to be removed to replace them if this is the problem. If you do a search on Mercedes B2 piston failure there's lots of how to's/videos to give you an idea.
 
Could you please provide a few more details of the vacuum leak that caused the harsh gear changes?
Was it a vacuum hose or linked to the vacuum modulator on the gearbox itself?
 
Check the vacuum line , follow it from the intake to the vacuum modulator. It could be disconnected or the modulator failed.

A quick google/youtube search will probably tell you everything that you need to know about this.
 
Could you please provide a few more details of the vacuum leak that caused the harsh gear changes?
Was it a vacuum hose or linked to the vacuum modulator on the gearbox itself?
Hi,
Sorry for the delay, but I'm not sure exactly what was done to fix the problem, and have been out of the country since. Will update when I'm back home.
 

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