Roger, assuming its a post 96 electronic 5 speed box, which are known to have problems in the valve gear circa 50-70+K.The best advice is to get it onto the computor diagnosis asap before the problem worsens & rectification starts costing 5 figure sums-which an unfortunate number of owners have already discovered to their chagrin.
As I recall you used to be in Germany but if you are in the midlands by any chance, I can recommend an excellent independant
dealer.
Simon T.
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Whist I don't know this gearbox, it sounds to me like fluid deterioation due to overheating. This will cause the changes to be slower than expected and accelerating after slowing down catches the box out. If this is the problem, the gearbox fluid will not be a normal bright red but brown, or at worst black. Changing the fluid may cure the problem initially but if overheating is the cause, then that will need to be cured.
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Many thanks for all these responses. I should have added:
* It's an August 1996 W124 machine, one of the last 124s to be built.
* It has only 35k on the clock.
* It has been serviced regularly by same the MB main dealer ever since new, the last service -- the big 36k service -- being less than a month ago, at which time I asked them to check that the autobox was working properly because I had noticed slight sluggishness in engaging drive or reverse. They said it was OK. It's definitely not OK now, the additional symptoms having emerged since the service.
* I am covered by an RAC Signature warranty, so am not quaking in my boots.
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The problem encountered with heavy braking then accelerating directly afterwards is just a case of catching the box out.
As you have the unit changing down to possibly second gear but if you are heavy with your right foot, the kickdown sensor will see that you want to accelerate hard and drop you down into first.
If you adjust your driving style to something slightly smoother such as on the approach to a roundabout do all your braking up to a car length away from the line , coast the last car length then accelerate this should prevent further kickdown.
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Thanks, Darren. My driving style had come to mind as a possible factor, but it is as gentle and smooth as I can make it, and always has been in 33 years of driving (I'm mean and don't like wasting fuel!). Note that I referred to "firm braking", not heavy or emergency braking, and some would call my firm braking gentle, I'm sure.
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Roger,
You mentioned that the car is covered by an RAC warranty. Does this mean that you bought it fairly recently? If so, could it have been standing on the dealer's forecourt for several weeks?
I ask this because it is not unknown for the valves in automatic boxes to get a bit sticky after a lot of standing, or just being shunted back and forth for a couple of months.
If this is the case, running a few miles with a lot of gear-changing (via kickdown or manually) should help free up the sticking valve.
Please note that this is only a suggestion based on very limited experience. It may be something completely different of course, like low fluid level (which should always be the first thing to check) or failure to generate the specified circuit fluid pressure.
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Just thought I'd mention that problems caused by sticking valves do not always show up straight away. They can happen a few weeks and quite a lot of miles after the car has been standing. I don't know why this is.
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Roger
Is this your e320 coupe? Mine has done 101k miles and the autobox is as smooth as new. Many years ago I had a Cortina 2000E auto with exactly these symptoms - caused by very low auto fluid level. I susupect that you have the same problem. The big 36k mile MB service includes autobox fluid replacement - was it filled to the correct level?.
If it was already starting to exhibit these problems before the service then it may have been losing a small amount of fluid over a long period of time. My W124 E300 diesel did this - from the pipe between the oil cooler and the auto box - it is prone to rusting through road dirt and salt thrown on to it - it is a bit of a known problem.
My advice is get back to the MB dealer asap there is clearly something wrong - suggest that they check the fluid level very carefully and that they also check the pipe to the oil cooler.
Let me know how you get on.
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Thanks again to all.
Yes, Steve, it is the E320 Coupé. It is booked into the dealers for 8 January. I have exposed the problem here to flush out all possible explanations.
I will try a session or two of intensive use to see if anything changes. I also have to confess that the car does sit for days at a time on my drive while I use the Golf. However, it is never used for short trips.
I much appreciate all the contributions here, which I will pass on to the dealers.
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Roger,
I would not use it until at least the fluid level is checked. Running it with low fluid will not help. It is interesting that you say that it sits for days on end without being used - it was when the e300 diesel was left for a few days that I first became aware of the leaking pipe. The transmission was slow to take up after it had not been used - caused by low fluid.
Surely the MB dealer can check the fluid level whilst you wait before 8 Jan - it only takes 2 minutes. If you are tempted to check it yourself follow the instructions carefully and beware if topping it up that only a small amount of fluid can have a big impact on the level on the stick.
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Thanks again Steve. I will heed your kind advice.
I composed this yesterday, full of hope:
I must re-acquaint myself with the concept of "welly".
Following Dizzy's suggestion, I've done a few kickdowns and have been through the box manually several times and, surprise, surprise, things seem to have improved. Not only have I been unable to replicate the previous behaviour when braking/accelerating, but the box seems to be operating more smoothly altogether and reverse engages more readily. I guess something was sticking. Perhaps I would have got here sooner if I had the faintest idea about what's going on within an automatic box. Applying welly to clear out a coked engine is a familiar concept, but I had not thought of applying it to the transmission.
Less pussyfooting, more welly. I'll see what happens over the next couple of weeks. Thanks again to all who have responded.
BUT
Today, although the performance continued to be smoother than it has been, I experienced the braking/acceleration thing again, and at one point reverse was very slow to engage.
I hope a clear diagnosis and solution to this will ultimately be of help to others.
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Roger,
What a shame that the improvement was only temporary. Still, it helps build up a picture for the technician.
I wonder if the improvement came about whilst the oil was still warm? Any valve/solenoid sticking would be less likely then of course. On the other hand, I suppose the level of the oil when warm would have been slightly higher than when cold and so the problem could still be caused by a low oil level.
As Steve says, a check on the oil level would take only a couple of minutes and it might not even need the car booking in. They would raise the car with the engine running (oil warm) then remove a plug and see that the oil is level with the hole. They could check the colour of the oil at the same time to confirm that there hasn't been any overheating or any breakdown of seals or brakeband (which I think unlikely).
As with all problems reported on this forum, it would be very helpful to be told of the outcome and I'm pleased that you intend to report back.
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Well, Steve, it looks like you were right. I've just had the fluid level checked and it seems that they failed to put the correct amount in when replacing it during the 36,000 mile service (Don't ask how much that cost, please). They've now done it properly and the behaviour of the box has changed instantly: snappier, smoother and, as yet, no slippage.
Thanks again to all. That's another main-dealer servicing story to add to my list, but at least they responded immediately to my request for a check. And it's another reminder to check out the simple things first before losing hair (not much to go now) over imagined catastrophes.
Over and out.
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Not quite out . . . I really ought to acknowledge the post from John Davis, which was the first to raise the fluid-level issue. Thanks, John.
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Modern Auto Boxes are getting far too clever and when they go wrong, they fail in a big [expensive] way or have 'bugs' such as yours Rog
MG-Rover Questions? forums.mg-rover.org/
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The "far too clever" bit applies to all aspects of modern cars, not just auto gearboxes. With electronic alarms, immobilisers, engine management systems, climate control, cooling systems and bulb failure systems, it's no wonder that 40% of the cost of a modern car is the electronics, rising to 60% in the next few years.
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It's just that I've had a bad week with automatic transmissions!
MG-Rover Questions? forums.mg-rover.org/
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Roger, I trust they'll be extending the warranty on the box to cover any possible damage that may have been caused by running low fluid?
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Funny you should mention this. The problem was dealt with on a "pop in on Saturday morning" basis. As far as I can see, the job was not formally booked into their systems. Yesterday afternoon I composed a letter to them asking for confirmation that the job was in their database, that they took responsibility for the error that was identified, and that the error had been brought to the attention of the fitter(s) who serviced the car.
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Dave, that's a valid point. However I'm sure Roger has nothing to worry about.
There was clearly enough fluid to fill the torque converter and the bulk of the operating system until some was called for to operate the servo and valve mechanisms, which dropped the level. Air would have been picked up but I'm sure that all the lubrication that was required would have been there.
The cooling capacity of the fluid was obviously reduced but the full capacity should be essential only when, for example, the car has a full complement of passengers and luggage and is driven for long periods in hot mountainous areas. Driving hard with frequent kickdowns etc. in our current ambient temperatures would not compromise the gearbox at all, otherwise I wouldn't have suggested it.
What really bothers me is that here we have yet another example of a main dealer being incapable of doing the job properly. One of my earlier postings (4th one down on
www.honestjohn.co.uk/forum/post/index.htm?v=i&t=66...5) related almost the same symptoms on a Ford Capri automatic where the main dealer didn't know how to fill the gearbox to the correct level. For a Mercedes dealer to apparently make the same error is unforgiveable, considering that probably more than 50% of Mercedes cars are automatics.
By the way, note that the Capri ran for many more thousands of miles without further problem. I also ran a 1965 Triumph 2000 automatic for many thousands of miles on low fluid levels because it constantly dribbled out of the back end. There was no rear seal on that early gearbox and any wear on the integral bearing area of the tailshaft housing led to leaks. I eventually cured this by fitting a new and very expensive tailshaft housing, though these days I would have machined and sleeved the old one.
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Strange, clicking on the link in my last posting doesn't work for me. If you also have trouble with this, just search for "Capri automatic" and click on the first item that comes up.
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I see what the problem is! I caught a closing parenthesis (that sounds grand, doesn't it?).
Try www.honestjohn.co.uk/forum/post/index.htm?v=i&t=66...5
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