Selector module

Mazi

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How much is it likely to cost to replace the selector module on my 2001 CLK 320 from an indy?
Is the selector module another name for autobox ECU?
 

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Your car has a selector module , and a gear box ECU, what is the car doing
 
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Mazi

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Your car has a selector module , and a gear box ECU, what is the car doing

Car is not shifting above 2nd gear and you cannot select reverse from D but you can select reverse gear from P.
you can move the stick through the gate with the engine off, the stick should be locked.
Also a bit of a thud when you select reverse or drive more so on first start up
 

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This fault sounds more like the plate is faulty, but that would not affect the gear shift lever
 

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Selector module replacement

Hi All

Reading this thread reminded me of a recent conversation I had recently with my indie concerning when to change the gearbox oil. His view was that if the oil looked clean and the gearbox was working correctly, leave well alone. He warned that an oil change would be expensive and it is a decision he would not take lightly.

Somewhere during the conversation he mentioned faulty selector modules. He described what it was, where it was and how to replace it. I concluded it was an expensive replacement job which would include replacing the oil. I told him my C230K had covered 121,000 miles with no transmission problems. My indie seemed surprised and I asked him for an explanation.

He informed me that the original design of the selector module fitted in the gearbox was prone to malfunctioning because fine splinters of metal shaved from rotating components through normal wear & tear could fall onto the electrical tracks on the selector module and short them out causing the gearbox to malfunction. The usual remedy, I am given to understand, was to remove the bottom of the gearbox, remove the selector module, clean it and refit it. Finally reassembling the gearbox and refilling it with fresh oil.

However, this remedial work was expensive and it became an all to common problem much to the annoyance of owners. My indie reported that it was so common that gearbox problems usually manifest within 100,000 miles, sometimes as early as 20,000 miles.

The standard solution was to fit a redesigned selector module, either when troubles manifest necessitating a gearbox inspection, or as a proactive measure to ward off future problems. Replacement may have been the subject of a recall but I have found no evidence of such an action on MB's part.

I confirmed that my C230K (2000) had a clean record as far as its transmission was concerned and this begs the question whether I've just been lucky or was a new selector module fitted before 89,000 miles when I acquired the car? My indie commented that my car's service records may not show a replacement if the work had been undertaken outside of a scheduled service.

Questions - Have I an original selector module or a redesigned one fitted? How can I find out? I believe I may be able to contact the original owner if he is still around but being rather elderly he may/may not be able to recall.

I gather the redesign includes some form of shielding over or around the electrical components of the selector module so that short-circuiting is greatly reduced. This simple redesign greatly extends the life of the selector module which can last the life of the gearbox. No further 'cleaning' is necessary.

Would any member have knowledge of this problem and could explain how the new selector module differs from the original design? I would also like to know in what year the retrofit was offered as a remedy? If my car has the new selector module then the retrofit must have been undertaken before 2004 when I acquired the car.

What does the selector module look like?

REGARDS

Phil
 

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There is no selector module in the box, you have an ECU that normally sits on the floor in the car, the sector module is on the gear shift control, this works in conjunction with the parking brake on some cars. the only electronic thing in the box is the plate that I mentioned earlier here, it is when this plate goes down, that the car can lock up in second, a missing speed signal / CAN signal can also cause this
 

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Selector module or 'plate' replacement?

There is no selector module in the box, you have an ECU that normally sits on the floor in the car, the sector module is on the gear shift control, this works in conjunction with the parking brake on some cars. the only electronic thing in the box is the plate that I mentioned earlier here, it is when this plate goes down, that the car can lock up in second, a missing speed signal / CAN signal can also cause this

Hi Malcolm

Is the 'plate' an electronic device that sits inside the gearbox, somewhere near the bottom, that operates solenoids and controls oil flow?

It maybe I have used the term 'selector module' to incorrectly describe what you refer to as the 'plate'.

If the 'plate' is not the sometimes troublesome electrical component then what is it my indie is referring to? I have never disassembled an automatic gearbox so I am curious as to what this electrical component looks like.

REGARDS

Phil
 

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Yes Phil the electronic plate that sits in the bottom of the box, easily removed from the bottom of the box, and most charge around £350 fitted with new fluid. I do not know if anyone has tried to clean one on a ultrasonic cleaner, what you say could be a good reason for them to fail, some thing shorts out the speed signal, and once this signal is lost , the box does not know what to do, so it locks up in 2nd
 

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Electronic plate

Yes Phil the electronic plate that sits in the bottom of the box, easily removed from the bottom of the box, and most charge around £350 fitted with new fluid. I do not know if anyone has tried to clean one on a ultrasonic cleaner, what you say could be a good reason for them to fail, some thing shorts out the speed signal, and once this signal is lost , the box does not know what to do, so it locks up in 2nd

Hi Malcolm

Yep, my indie did say it would cost around the £300 mark to replace the 'plate' and refill the gearbox with fresh oil.

He described the 'plate' as an electronic circuit board but this conjures up a picture of the sort of thing you might find in a computer, radio or TV except much less sophisticated. However, I would regard a gearbox as a hostile environment (heat, moisture, contaminants) for any electronic circuit UNLESS its design was particularly robust. The 'plate' may therefore only have a superficial resemblance to what I consider an electronic circuit card to be.

Thanks for confirming that metal splinters could interrupt the plate's correct functioning.

Is the plate surrounded by air or gearbox oil?

'Locking up in 2nd' is a 'get-you-home' feature?

REGARDS

Phil
 

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I am trying to pick up as many faulty parts that I can, just to see what can be fixed, I will get one soon and put up an answer. Oil / fluid is totally non conductive in its self, as it is the separation of the molecules that make oils and fluids what they are, with metal mixed in then this is another story
 

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HI.As Malcolm has explained the speed sensor on the electro plate is designed to be emersed in oil as is the temp sensor which sits next to the speed sensor they can both fail.the star machine is a great bit of kit, and all these parts can be read in actual values. which saves alot of time
 

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Plate is oil immersed?

HI.As Malcolm has explained the speed sensor on the electro plate is designed to be emersed in oil as is the temp sensor which sits next to the speed sensor they can both fail.the star machine is a great bit of kit, and all these parts can be read in actual values. which saves alot of time

Hi M.B.S.

So, the plate is oil immersed. I thought it might be.

REGARDS

Phil
 


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