justin218

The other day on the highway I noticed shifting was odd and engine revs were high. Once I got off the highway at a stop I couldn't then get the transmission to re-engage to go forward until I turned the car on and off. I was able to limp it to a parking lot but in the process there were a couple times I had to rev the engine very high to get the transmission to kick in to move the car.

Couple hours later I limped the car home but it didn’t seem like it could really shift and I couldn’t get above 25mph or so. A check engine light came on and it is P0730. It’s really not drivable and sounds rough. I noticed an odd whine and recorded it:
Its a 2008 E350 with 140k miles. Does it sound like it’s totally shot or maybe a transmission fluid change or something could sort it out? If it needs much more than that I’m not sure if it’s financially worth it

Plutoe

forget all the bstube data as the 730 is an obd fault that indicates there is a transmission issue bla bla ------now what you need is less bs and or someone with MB DAS to diagnose the transmission for faults as anything else is more bstube with no results

justin218

As an update to this, I was curious if the transmission fluid was low for whatever reason. So I opened the drain pan bolt but plenty of fluid came out. As long as the 722.9 transmission pan little chimney was still in place I wouldn't have expected much to come out.

I had a liter of Shell ATF 134 on hand so I removed about 1L of the old fluid (it was quite brown) and replaced it with the new fluid. After I did this the transmission seemed fine amazingly enough, it was shifting ok and the whine went away... for about 5 miles. Then the whine came back and the shifting is real rough/off again. But it can at least shift and get it above 25 mph now. Hoping a more complete transmission fluid change might sort it out.