Hey all, I'm a new member here and a relatively new Mercedes owner. Got a well-maintained 1999 E320 wagon with just under 219k on it. Car has worked great for almost 9 months. Only issue I've ever noticed with transmission is that, when I first start to drive the car, it takes longer to shift from first to second than usual which I assumed is just a warmup feature.

Yesterday my wife calls me saying it has just completely lost power while she's driving (she had just left the house and only gone maybe a mile). She rolls to a stop in a parking lot. 10 minutes later, she is able to move the vehicle slightly again, but then no power again. Hour and a half later, I'm able to get it home with no issues. I have pored over posts on similar issues, but still not quite certain where to begin. I drove it up to advance this morning and got the codes po400, po700 and po715. I put the car on blocks to attempt to get a warm reading on the trans fluid. While the car is on blocks, I can shift seemingly into every gear and the rear wheels both turn appropriately. After 5-10 minutes, I begin to hear an odd whirring/clicking noise from the engine compartment upon acceleration when under load but not when in neutral or park. I have my son man the pedal so I can look for the source of the noise, but I'm not able to ascertain anything other than that it's coming from the engine itself, possibly to the driver's side. The noise then stops and with it all motion from the drivers' rear wheel. Curiously, now the passenger's rear wheel turns forward slowly in all gears except park. The trans doesn't seem to be shifting at all really, but some slight engine noise shifts can be detected when the shifter is moved. Nothing like normal. I was not able to get the transmission up to 80 degrees C because I can't drive it, but at about 50 degrees the measurement I got from the trans fluid dipstick was over the full mark. A very small amount of white gunky stuff was observed at the bottom of the dipstick, which had not been there when cold.

I'm going to replace the ATF and the filter; what else should I do? I'm considering doing the contact plate as well. Could the torque converter be shot? Any advice is helpful. I have seen lots of similar issues that are usually unresloved but nothing quite like this so I apologize if this is a redundant inquiry. Thank you.

 

Mine's first shifts of the day are frequently, but not always wonky. Mostly it works normally. Moody for sure.
For me, when it's not shifting properly the trick is to pull over, put it in Park for 5+ seconds and it will work normally for a while. I've gotten in the habit of backing out of the driveway, putting it in Park, then driving. Mine has about 125,000 miles and had the oil & filter changed around 60k and again at 120K, so I think it's something else. I'd like to deal with it before it leaves me in a lurch.

I'm looking forward to following this thread. I'm hoping this can be affordably fixed. Anyone know a good MB tranny shop in Atlanta area?

 

As always, my experiences are from another cars, namely domestic classic V-8s (Various GM, Ford and Mopar). So this may not apply to our beloved MB, but want to share it so it may give you an idea as to what's wrong or how serious. Also, been both shade tree and professional mechanic for over 30 years. Have rebuilded more than several car engines, along with trans and some motorcycle engines as well.

With that been said, if you haven't already, have you check the level and condition of your trans fluid? Trans fluid are usually red in color. If it's brown or anything darker, change your fluid. This is easier said than done. If you can find a good, reputable trans shop near you, take it to then and have them pressure flush the trans. I know it's expensive, but this is the only way (well, not only. Little later on that) to make sure you have all the old fluids flushed. Draining the pan is not enough as about 60 - 75% of the fluids are in the converter. So only way to do this one time is to have it pressure flush. Second method, you can do it yourself but more money and time consuming. Drain the fluid from the pan (while you at it, make sure to change the filter as well), refill it with proper fluid and level, run the car for few miles to circulate the fluid (5 minutes drive should do it), park it to cool it down and change the fluid again (do this few more times and MOST of the old fluids should be out). Please remember, this is just to change the fluids. Not to a cure to your trans problem. You now have baseline for your trans diagnostic with fresh new fluid.

Now, from my past experience, if you hear a whine from your engine compartment, it USUALLY is a good indication of low fluid. Now for the bad news. If indeed was a low fluid and the whine is from your transmission, your trans pump is toast. Don't take me wrong. Your trans may still work, and it will continue to work until the clearance on the pump vane are too much and you will be stuck, only this time, your pump can't send fluids to anywhere so you are really stuck. Your hour and a half cool down is typical symptom of trans at end of it's life. When cool down, your fluid are thicker and clearance is tighter, pump or whatever is worn is able to function. When it get hotter, fluid is lot thinner and clearance is lot bigger so it won't be able to circulate the fluid. I'm not sure what you mean by "takes longer to shift" but flaring between shift, most often between first and second (as these gears are used more often than the higher ones) are good indication of worned out transmission.

Lastly, again, my experience are from other makes and models, so it may not apply to our beloved MB as I just got my E320 last June. So I don't have enough experience on these MB and they are totally different beast from other cars, electrical included. So I hope I'm wrong about this. Otherwise, its' a expensive fix/repair unless you can get yourself fairly cheap good used trans.