OM606 whine noise at idle in gear
 

On my '97 E300, this afternoon on my way back from a long trip to the south, my engine (powertrain) stated making this wierd whine noise when the vehicle was completely stopped and in any gear. I noticed it by waiting at a stop light in NY and I hear this odd loud whine, like a power steering pump being strained is the best I can explain. When letting off the brake and letting the car cost, say 2mph the noise fades out and everything is back to normal. Only when the car is at a total stop and in any gear, except neutral or park. My belts appear to be tight and not loose. Can it be an engine mount(s)? With the hood open and another person applying their foot on the brake and shifting into gear and out of gear there appears to be some decent engine movement, just by quickly guessing the engine shifted to the right about 1-1.5 inches? That seems like a lot and why I am thinking it is the engine mounts. My car now has 167,500 or so miles on it and no idea if the original mounts were ever changed...

Any ideas guys?

source of whine?
 

Since it only makes the noise while in gear stopped--don't ever stop.

Seriously, its definitely coming from the transmission and sounds like the pressure control valve is screaming a bit. Sometimes a clogged filter will cause the oil pump to 'scream'. Try changing the filter and fluid. Another potential cause is mechanical rubbing inside the 'fluid coupling' (torque convertor). That aint' cheap to fix.

I presume the shifting is still good, smooth, not slipping and accelaration performance is unchanged. If acceleration is sluggish--look to damaged 'fluid coupling'. If performance is normal, oil and filter change may quiet it down.

The oil pumps are a known weak area and tend to fail by first scoring the plain bearing that supports the 'fluid coupling' neck, then that bearing seizing on the 'fluid coupling' neck and then turning in the oil pump housing, causing a sudden large ( maybe several oz/min)leak of transmission fluid when running.

I have noticed that my serpentine shock is really worn out, the upper bushing is shot. I'm gonna replace that tonight when I get home. When I had the hood open at one point in Park it was making a noise and I pushed on the top of the shock with my hand and it quieted it down a lot.

Also the problem has been intermittent. I figure if it is with the transmission is would be consistenly making the same noise everytime by this point.

I'll report back.

Took the E to my local mechanic today and they did confirm that it is the transmission. Could not say exactly what it is but I opted to have the fluid replaced and filter as a start. Last time the fluid and filter was replaced was approx. 40K ago. We'll see what happens....

Any idea how much these transmissions go for as a rebuild? Any MB tranny specialists anyone can recommend in Connecticut or South Carolina?

Update...
 

Went to my indy and got the car back. The noise is coming from the oil pump for the transmission. I took it for a test drive after they replaced the fluid and filter and the car shifts like butter but still has that same noise. When they drained the previous fluid they said it wasn't too bad at all, just some dirt but not dark fluid like on a burnt transmission. My indy will do some homework to find out how much it will cost to get that pump and to replace it. Fortunately they won't have to remove the transmission in order to replace the pump, apparently it's located in the bell housing.