C320 W203 auto gearbox
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Joined: Nov 2015
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W203 Merc C320
C320 W203 auto gearbox
Hi Guys,
I wonder if anyone can give some advice on my 2001 C320 auto gearbox.
The car runs well and changes gears very smoothly but after a few Km's a whining sound comes from the box (as if its not getting oil) and then it starts slipping. All I do is turn the key off for a short while and start again and off she goes again for a few Km's more.This is a second hand box that was installed as the first one also had simular problems. The oil and filter has been changed.
Could I have maybe used the wrong ATF oil (off the shelf stuff at most spare shops) or is there an electronic problem that needs to be checked? Is there anything I may be able to do myself?
Thank you
Pierre
I wonder if anyone can give some advice on my 2001 C320 auto gearbox.
The car runs well and changes gears very smoothly but after a few Km's a whining sound comes from the box (as if its not getting oil) and then it starts slipping. All I do is turn the key off for a short while and start again and off she goes again for a few Km's more.This is a second hand box that was installed as the first one also had simular problems. The oil and filter has been changed.
Could I have maybe used the wrong ATF oil (off the shelf stuff at most spare shops) or is there an electronic problem that needs to be checked? Is there anything I may be able to do myself?
Thank you
Pierre
Junior Member
Joined: Apr 2015
Posts: 63
Likes: 3
From: Minnesota
2004 C320 4matic sedan
Thread Starter
Newbie
Joined: Nov 2015
Posts: 2
Likes: 0
W203 Merc C320
The box has been flushed and the correct oil used but the problem is still there. The box runs smooth without any problems until the engine temp reaches 80 deg C. My mechanic says there is no oil pressure to the oil cooler and had the pump checked out which is ok.
All the gearbox guys we went to want to replace all the parts in the box which is very expensive and I dont feel this is neccessary as the box runs perfect when cold.
Is there maybe a thermostat or valve that controls the oil to the cooler and opens when the oil becomes warm, or any other ideas
Thanks Guys
All the gearbox guys we went to want to replace all the parts in the box which is very expensive and I dont feel this is neccessary as the box runs perfect when cold.
Is there maybe a thermostat or valve that controls the oil to the cooler and opens when the oil becomes warm, or any other ideas
Thanks Guys
Junior Member
Joined: Apr 2015
Posts: 63
Likes: 3
From: Minnesota
2004 C320 4matic sedan
The box has been flushed and the correct oil used but the problem is still there. The box runs smooth without any problems until the engine temp reaches 80 deg C. My mechanic says there is no oil pressure to the oil cooler and had the pump checked out which is ok.
All the gearbox guys we went to want to replace all the parts in the box which is very expensive and I don't feel this is necessary as the box runs perfect when cold.
Is there maybe a thermostat or valve that controls the oil to the cooler and opens when the oil becomes warm, or any other ideas
Thanks Guys
All the gearbox guys we went to want to replace all the parts in the box which is very expensive and I don't feel this is necessary as the box runs perfect when cold.
Is there maybe a thermostat or valve that controls the oil to the cooler and opens when the oil becomes warm, or any other ideas
Thanks Guys
It is really strange that no transmission oil is flowing through the lines to your cooler.... because I used those lines to flush my transmission (when relatively cold) and the oil flowed with gusto.
Was improper tranny fluid used in it earlier (per your first post)? Has it truly been flushed, or just a pan drop/partial change? Does fluid flow through the cooler line at all, when cold or warm - if not, how was it flushed?
The relatively easy DIY things on this box include:
- fluid and filter change/flush - MB said it is good for life, but this is turning out to be only "good for the warranty period". Must use the proper fluid! I used the Febi 236.14 fluid.
- replace pilot bushing (electrical connector)- because they leak, getting oil in the wiring harness and into the transmission control computer causing all kinds of havoc
- replace conductor plate - tend to fail fairly often
Also, I did some work on my valve body, installing some Sonnax valves, which was a little more complex.
Finally, find someone with a STAR computer to reset the transmission adaptations, this was critical to getting my tranny working properly after I did all the above!
Last edited by dmac5356; Nov 30, 2015 at 07:21 PM. Reason: typo
