1993 E320 Cabriolet 5 speed transmission

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riffraffjazz

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Hi, I have a 5 speed automatic 1993 E320 Cabriolet. Problem is that it is not going to 5th, removed transmission control module (TCM) and the car shifts straight from 3rd to 5th, (as I was told it would), good to know I have 5th.
I want to know where the "D" switch is, I have removed center console as I've been told it is located there, all is see is a couple of small shafts heading front and rear. I have read that if the switch is faulty you get no 5th.
One sheet says to check for loose connections at the Throttle valve switch and between TCM and transmission, both seem to be OK.
Any help with "D" switch location would be appreciated, Cheers, Paul.
 
I have had the 5th gear control module fail on one before causing this issue. This 5 speed box is a real pain to fix. There is a company called Mackie Transmissions that are very good on this 'box
 
Hi, The transmission is a replacement, 2nd hand but it shifts fine, I will try another control module just in case it's that.
But still would like "D" switch location. Cheers, Paul.
 
Hi, The transmission is a replacement, 2nd hand but it shifts fine, I will try another control module just in case it's that.
But still would like "D" switch location. Cheers, Paul.

I should have thought the switch is under the gear lever, no?

722.5_Gearlever.jpg

The switch on my 722.5 box (300CE-24) is Part 80 in the diagram above. It is located under the gear lever to the right of where the arrow from Part 77 goes. I would call that bottom right when sitting in the car with the centre console off. Switch 77 itself is in the top left, er, if you follow me?

I had switch 80 out 2 days ago as I lost 5th when the weather suddenly got hot. I tested the switch and found it was not making contact - it is a "normally closed" switch. A generous dose of contact cleaner and repeated operation of the switch restored normal service.

And yes, Mackie in Glasgow rebuilt mine as part of a general restoration - around £2K.

Good luck.

RayH
 
 
I should have thought the switch is under the gear lever, no?

View attachment 96039

The switch on my 722.5 box (300CE-24) is Part 80 in the diagram above. It is located under the gear lever to the right of where the arrow from Part 77 goes. I would call that bottom right when sitting in the car with the centre console off. Switch 77 itself is in the top left, er, if you follow me?

I had switch 80 out 2 days ago as I lost 5th when the weather suddenly got hot. I tested the switch and found it was not making contact - it is a "normally closed" switch. A generous dose of contact cleaner and repeated operation of the switch restored normal service.

And yes, Mackie in Glasgow rebuilt mine as part of a general restoration - around £2K.

Good luck.

RayH
Thank you very much Ray, I have sorted my 5th gear problem out, I found the codes for the Transmission control module, they are not listed on the W124 code sheets and when tested got the reading number 9 control valve, took me a while to figure out what it is and it turns out to be the valve at the end of the kick down cable.
I also read that you have to clear the codes or it just locks out 5th gear. On resetting I could hear what sounded like a relay click, (could be my imagination) but in any case I have 5th gear and all is running like it should, time will tell but if I get that fault again I will adjust the kick down cable as I have also read if it's too tight you can't get 5th.
I now have a folder on auto transmission diagnosis and now have the location of all the parts involved, this has been a journey. Without the help from people like yourself it would be impossible and I am very grateful.
I should add that it would be a long drive to get my transmission rebuilt over there as I'm in Australia. Thank you again, Paul.
 
Thank you very much Ray, I have sorted my 5th gear problem out, I found the codes for the Transmission control module, they are not listed on the W124 code sheets and when tested got the reading number 9 control valve, took me a while to figure out what it is and it turns out to be the valve at the end of the kick down cable.
I also read that you have to clear the codes or it just locks out 5th gear. On resetting I could hear what sounded like a relay click, (could be my imagination) but in any case I have 5th gear and all is running like it should, time will tell but if I get that fault again I will adjust the kick down cable as I have also read if it's too tight you can't get 5th.
I now have a folder on auto transmission diagnosis and now have the location of all the parts involved, this has been a journey. Without the help from people like yourself it would be impossible and I am very grateful.
I should add that it would be a long drive to get my transmission rebuilt over there as I'm in Australia. Thank you again, Paul.

Good news, well done.

I bought a new transmission control module (HGS) and installed it to ensure it was OK. It wasn't. It reported error 9 control valve and I couldn't clear the code. I replaced my 30 year old original and all is well.

Interesting about the tight cable. Shall give thought to that.

R
 

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