Ive got some 7g box anomalies on 2008 320cdi CLS - they are not huge problem but slightly detract from what is a great car. I'd really like to get them sorted at some point. Status of car as follows
1. Sometimes sticks in gear up to exactly 3000rpm then changes up to next gear and sticks up to 3000 etc. After about 2 minutes it then reverts to normal and changes up at normal rpm levels. This happens about every third or fourth journey (ish) and only ever once on that journey. Sometimes on the way home from work it will happen at exactly the same point in the journey! Turning corners sharply seems to provoke it but I haven't conclusively proved this. Manually right flick on gear stick is ignored when it's in this "temporary sticking gear mode". Can happen on flats or inclines. This never happens from cold.
2. Hard shift from 2 to 1 when cold. Softens as things warm up but occasionally there will be a hard downshift from 2 to 1 after a long journey. Sometimes coming to a stop on an incline can provoke it after its warmed up. It never happens twice in succession though if it's up to temperature.
3. Change downs from 3 to 2 (could be 4 to 3 - it's hard to tell sometimes) can feel a bit "grabby" certainly not a jolt or thump but feels as though it could blend speeds little better while changing down. Feels like a slightly and momentary harder press on the brake peddle while coming to a stop (either in a gentle stop or a quick stop). It's almost like it aids braking but not in a smooth consistent way. It's slightly more noticeable when cold. Sometimes when travelling up to 40mph or so and down to low speeds you can't feel anything on the down changes (perfect changes) but almost always you can feel it when slowing down from higher speeds.
4. Can sometimes have quite a delay when putting your foot down from standstill and it taking off (roundabouts etc - eek!). This does sometimes vary though, other times it flys off the line instantly. Perhaps it's a hormonal!!! It Used to go into a soft limp mode (no warning lights) where by it would change up very early and barely no power. After using shell v plus for a while this has not happened for months. Suspect egr and turbo were mucky and cleaning agents in v+ cleaned things up a bit. It also used to lurch on/off if you 50%+ accelerated from cold/warm - this too has gone now.
5. S mode does raise gear change rpm points hence appears to be working although I don't use it that much to be honest. But at least once a week it gets full beans to blow the dirt out - well my excuse anyhow.
Some of the above could just be trates of the box design but with no codes showing its niggling me a bit. After hours of research online its not lead me to any firm conclusions but my gut tells me it's is a misbehaving valve in the valve block - total guess... The problems are not 100% repeating all the time , only the 2 to 1 hard shift when cold is virtually guaranteed. I could have more than one fault of course!
Is a gearbox and engine software update worth a shot? If so, can a good Indy do this as opposed to MB workshop?
Opinions very welcome.
- No errors or warning lights on these issues
- 90k miles
- Properly serviced by good Indy
- Has had 2 oil and filter changes. Last change, oil looked pretty clean
- No STAR errors/codes showing
1. Sometimes sticks in gear up to exactly 3000rpm then changes up to next gear and sticks up to 3000 etc. After about 2 minutes it then reverts to normal and changes up at normal rpm levels. This happens about every third or fourth journey (ish) and only ever once on that journey. Sometimes on the way home from work it will happen at exactly the same point in the journey! Turning corners sharply seems to provoke it but I haven't conclusively proved this. Manually right flick on gear stick is ignored when it's in this "temporary sticking gear mode". Can happen on flats or inclines. This never happens from cold.
2. Hard shift from 2 to 1 when cold. Softens as things warm up but occasionally there will be a hard downshift from 2 to 1 after a long journey. Sometimes coming to a stop on an incline can provoke it after its warmed up. It never happens twice in succession though if it's up to temperature.
3. Change downs from 3 to 2 (could be 4 to 3 - it's hard to tell sometimes) can feel a bit "grabby" certainly not a jolt or thump but feels as though it could blend speeds little better while changing down. Feels like a slightly and momentary harder press on the brake peddle while coming to a stop (either in a gentle stop or a quick stop). It's almost like it aids braking but not in a smooth consistent way. It's slightly more noticeable when cold. Sometimes when travelling up to 40mph or so and down to low speeds you can't feel anything on the down changes (perfect changes) but almost always you can feel it when slowing down from higher speeds.
4. Can sometimes have quite a delay when putting your foot down from standstill and it taking off (roundabouts etc - eek!). This does sometimes vary though, other times it flys off the line instantly. Perhaps it's a hormonal!!! It Used to go into a soft limp mode (no warning lights) where by it would change up very early and barely no power. After using shell v plus for a while this has not happened for months. Suspect egr and turbo were mucky and cleaning agents in v+ cleaned things up a bit. It also used to lurch on/off if you 50%+ accelerated from cold/warm - this too has gone now.
5. S mode does raise gear change rpm points hence appears to be working although I don't use it that much to be honest. But at least once a week it gets full beans to blow the dirt out - well my excuse anyhow.
Some of the above could just be trates of the box design but with no codes showing its niggling me a bit. After hours of research online its not lead me to any firm conclusions but my gut tells me it's is a misbehaving valve in the valve block - total guess... The problems are not 100% repeating all the time , only the 2 to 1 hard shift when cold is virtually guaranteed. I could have more than one fault of course!
Is a gearbox and engine software update worth a shot? If so, can a good Indy do this as opposed to MB workshop?
Opinions very welcome.
