Gear shift is too soft and slippy

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IanES

New Member
Joined
Sep 12, 2009
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9
2003 ML270 CDI with auto transmission

Gear changes are VERY soft and especially the change 3 to 4 the gear appears to slip for a moment during which time the engine flares up for a moment.

I've heard people complaining about hard shifts looking for ways to adjust but mine are the opposite - I guess the same adjustment would apply to me - just the other direction.

Is there a vacuum valve that can be adjusted to increase the pressure ?

Any assistance is greatly appreciated.

Thank you very much
Ian
 
Sounds like you could be low on Transmission fluid. I'd get that checked first. Would be best to get it changed if the car has done over 50k miles.
 
Is there a vacuum valve that can be adjusted to increase the pressure ?
5 speed is all electronic so nothing to adjust really.

How much does it flare?

A few months ago I noticed mine flaring by about 2-300rpm if changing from 3 -> 4 at about 2500rpm - on steady pull aways up to 60mph. Quicker pull aways where the change was over 3000rpm were fine, as was dawdling around town below 2000rpm.

Since then it seems to have improved - or I've stopped watching the rev counter like a hawk (changes were smooth the flare was only really detectable by watching the rev counter). Oil level was fine - but I did do a half (4litre) change (which I was planning anyway) - so perhaps the nice new detergents in the ATF cleaned the valves in the box up a bit.

Not much help really - but I would be interested to know if the symptoms match.
 
Has yours got the s/w button or whatever they call it on the newer cars? try the other setting.



Lynall
 
A few months ago I noticed mine flaring by about 2-300rpm if changing from 3 -> 4 at about 2500rpm - on steady pull aways up to 60mph. Quicker pull aways where the change was over 3000rpm were fine, as was dawdling around town below 2000rpm.

Yes, that's pretty much it - same symptoms.

My problem is that I just bought the car about a month ago so I really want to get this sorted while I've still got some warranty/goodwill with the dealer. I bought the car from a Ford main dealer - I took the car back to him last week and he sent it up to the local MB dealer to be checked over and the MB dealer plugged it into the diagnostics etc. went for a test drive and reckons there's nothing wrong. I reckon he just blasted round the block and, just like yours, the problem doesn't happen when you're pushing it a bit so he probably wouldn't have noticed it.

Obviously the flaring isn't bad enough to cause an error to be logged in the memory but my fear is that a clutch is on the way out and the day after the warranty expires it'll start getting worse.

It's a diesel so a little noisier so notice it even when I'm not watching the rev counter.
 
Sounds like you need to take the MB tech for a drive and demonstrate the fault.
 
Sounds like you could be low on Transmission fluid. I'd get that checked first. Would be best to get it changed if the car has done over 50k miles.

If anything the fluid is a little high. I've recently purchased the car and I'm wondering whether the previous owner also noticed the problem and, not having a dip stick, he chucked a bit more fluid down there just to see what happens.
 
OK, I have a confession.

The very same day that I picked up the car it went into limp mode - stuck in 2nd gear - I stopped, switched off, waited a bit, restarted and carried on as if nothing had happened.

I have access to the equipment to read out the faults ( I know a guy who knows somebody else) and there were a couple of faults in there but no idea how old. Something about invalid ratio etc. I kick myself now because I didn't make a note of the fault codes before clearing them because I was so sure there was a genuine fault and that after a quick spin the fault code would re-appear. Thing is no matter how I drive now I just can't make the fault codes re-appear.

My problem is that I can't tell the dealer or the MB tech about the limp mode and that I've cleared out some error codes otherwise they're just going to tear up any warranty/goodwill.

Or what do you guys reckon ?
 
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They might not have been relevant as we get lots of faults listed on the trucks and whilst you are after info on 1 fault there may be 10 seperate codes listed and 9 arent even anything to do with the fault you are repairing, ie can and comm errors.

But on the other hand the fact it went into limp mode means the car was pretty certain it saw a genuine fault, maybe just elec fault which will be cheaper than a new box.

Ring a couple of gearbox places and ask them the question, all the ones i rung were friendly enough and all had the same answer to my question.



Lynall
 
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But on the other hand the fact it went into limp mode means the car was pretty certain it saw a genuine fault, maybe just elec fault which will be cheaper than a new box.
Lynall

The first time I drove the car I had to enter the radio code - this shows that the battery had been disconnected recently. I read on other forums that disconnecting the battery can cause spurious faults causing the car to go into limp mode shortly after ? Anyone heard that ?

That's why I cleared the faults kind of expecting the current/genuine fault(s) to re-appear.

I'm booked in to the local MB workshop tuesday morning to go for a test drive to demonstrate the problem.

I'm not the type of bloke who spends half his life "demanding satisfaction". Even if they do eventually fix it I'll have spent hours of my life trawling back and forth to workshops and I've got better things to do with my life. So if the fault isn't confirmed on tuesday I'll just leave it at that. I know I'm not going to need a new box - I can get one from a breaker and fit it myself if this one ever goes t*ts-up - it probably won't.
 
A ratio error roughly translates as a slip through one or more of the gears............ not good.

Having worked on a few of these wth exactly this type of fault I can tell you that they are prone to premature valve body wear and it usually manifests in the form a a crap 3-4 shift or an equally rubbish 4-3 coastdown shift, it can and often does affect the other gears. If you drive it a bit harder then the internal pressures are raised in the hydraulics and this masks the problem somewhat.

First thing is to check the fluid level, but I would assume the MB dealer will have done that already.
 
Having worked on a few of these wth exactly this type of fault I can tell you that they are prone to premature valve body wear...
When I was googling the symptoms, valve pack replacement seemed to be the solution.

Ian - will be interesting to see what MB think about that.
 

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