stumo
Senior Member
- Joined
- Sep 4, 2008
- Messages
- 431
- Reaction score
- 66
- Location
- VIC, Australia
- Your Mercedes
- ML270CDI x3 2002,03,04 | Sprinter 316CDI 2003 LWB
I tried getting input on this from a w163 specific forum, but I got no real takers. So anyway here goes...
My 722.6 transmission in my W163 ML270 runs perfectly but it makes a horrible whine sound when on overrun in 2nd gear. It is far worse when engine/trans is cold, but it is still there when hot too. I can hear it inside the cabin with windows shut when cold, have to have window open to hear it when hot.
It is an expensive sounding noise, it kind of sounds like a big electric motor sort of whine sound. I have heard that same sound from other auto transmissions in many different cars when holding them in lower gears on overrun, just not as loud as mine. Trouble is the ML likes to automatically hold on to lower gears when going down hills at urban speeds, so it is constantly reminding me, and to be honest it is driving me nuts.
So does ayone have any advice/input, I have recently changed 4l of fluid (of about 8l total) and filter (with genuine MB parts), but no change to the sound, oh, and its done 145k miles, with an unconfirmed filter and fluid change about 20k miles ago by the previous owner too. The fluid I changed was dark brown but not burnt or full of metal.
I do have a recurring P2600 stored fault in the EGS system using carsoft, never get the error live, so I assume it is happening during cranking. I beleive that fault is to do with the main power supply to the EGS controller (transmission ECU). I don't know if this is related to the whine, but who knows?
My 722.6 transmission in my W163 ML270 runs perfectly but it makes a horrible whine sound when on overrun in 2nd gear. It is far worse when engine/trans is cold, but it is still there when hot too. I can hear it inside the cabin with windows shut when cold, have to have window open to hear it when hot.
It is an expensive sounding noise, it kind of sounds like a big electric motor sort of whine sound. I have heard that same sound from other auto transmissions in many different cars when holding them in lower gears on overrun, just not as loud as mine. Trouble is the ML likes to automatically hold on to lower gears when going down hills at urban speeds, so it is constantly reminding me, and to be honest it is driving me nuts.
So does ayone have any advice/input, I have recently changed 4l of fluid (of about 8l total) and filter (with genuine MB parts), but no change to the sound, oh, and its done 145k miles, with an unconfirmed filter and fluid change about 20k miles ago by the previous owner too. The fluid I changed was dark brown but not burnt or full of metal.
I do have a recurring P2600 stored fault in the EGS system using carsoft, never get the error live, so I assume it is happening during cranking. I beleive that fault is to do with the main power supply to the EGS controller (transmission ECU). I don't know if this is related to the whine, but who knows?
