cneedham810

Been to a few shops to have them look at the tranny. So far all I've gotten is the need to rebuild for 2500. I am putting out the PO715 code/input/turbine speed sensor. The car is operating semi-normal at operating temp but when the car is firt starting in the morning or at anytime for that matter it does all kinds of things. It neutralizes, won't go out of 1st gear, vibrates bad when you step on the gas only for a few seconds though. But at operating temp the car shifts smoot through all gears and drives like when I first bought it.

Do I really need to rebuild? Or will replacing the ensor fix the problem.

Oh yea my fluid is burnt bad too. Any help would be appreciated. First transmission problem I've ever had.

ohlord

you r/r the trans.Do the fluid and filter change the sensor that is showing the code is prone to faults from the graphite that darkens the fluid.what year?
diy on benzworld.org w210 section diy area.
After the drain reset the system and cross your fingers.
I have the dip stick for $40.
Good luck.

okay I saw what year so you don't have a tq.converter drain.Do the partial drain and let it drain overnight or go to a shop and have it drained,mb spec fluid only

zam2000

I have the EXACTLY the same thing happened to my W210 2 years ago. Car would not come out of neutral when cold, shake a bit, and act normal once warmed up. I tried oil change, trans service. Problem went away for short periord and eventually come back.

Eventually, the trans went out, and I have it rebuilt, by Indy shop specialized in Mercedes/BMW. I was told that the first ring/gear set in the trans (used for 1/2 gear) broke. However, the shop replaced all three gear sets.

Can ran smooth for 30K mile, and then same problem appear again. Shop did diagnostic, and told me trans went out again !!!. Even the Mercedes mechanic who rebuilt my trans pulled his hair and wonder what happened.

I did some research and found something interesting: in the first few years of the 722.6 trans (use in 97/98-later W210 and most other Mercedes), there's a flaw in design/manufacturing of the transmission planetary gear. The problem lead to the planetary gear warp & out of alignment, and eventually took out the ring set(s), and hence ruin the transmission. Notice that the rebuild process often involved ring set & bearing replacement, but the planetary is untouched, so even if the trans is rebuilt, the problem would eventually come back. The issue was mostly resolved w/ 722.6 built after year 2000. Not all early 722.6 have this problem, but if it ever happens to the trans, and not handled/rebuilt properly, problem would come back. Do your search on Mercedes forums, you would see that lot of people have their trans rebuilt by Indy shops, and keep having problem w/ their trans afterward.

You might wonder why the Mercedes mechanic who earlier rebuilt my trans wasn't aware of this problem: it's not something Mercedes instructs all their mechanics. They don't rebuild trans at dealer shop, but simply replace broken w/ the remanufactured one. As the matter of fact, most Mercedes mechanic don't deal w/ internal of the trans, beside gasket/filter/sensor replacement. Only the ones that get sent to Germany for training to know EVERYTHING about Mercedes, or through deep experience in its trans are aware of this problem. Btw, Mercedes don't build this trans, it's another manufacture. Same trans being used by other European car, Jag is one of them

I didn't go w/ the rebuild again, instead trading in the car for a W220. When I drop my S in another Mercedes shop in Moterey Park, and told them about the problem w/ my W210 (too see how much they know about Mer trans), the shop owner, who work 20 years for Mercedes dealer, said exactly the same thing: it's best to buy the remanufactured one from dealer if your 722.6 broke, otherwise, it's a waste of money, and problem would eventually come back.

This is one of the reason why dealer replace 722.6 when it goes out, with the manufacture rebuilt one using updated planetary gear, and why it costs a small fortune. Indy/trans shop often changed broken parts, but don't touch the planetary gear, since it cost as much as changing the entire trans.

So do some research. Go to mercedesshop forum and search for "722.6", "planetary", "transmission". You would eventually see the gentlement post. He's been Mercedes mechanic his whole career, and very knowledgable about Mercedes problem. Google around, you would see it to.

And when it comes to trans, let the pro handle it, and take it to them as early as possible, don't try any silly DIY. It might cost you more up front, but often help/save you in the long run. Most, if not all, people here (myself included) have no clue how complex it is.

ohlord

the money,before you declare it dead,do the fluid change.Most notably with the fact it shifts and operates fine,when it does and when it doesn't it is the speed sensor fouled by the dirty fluid.

hadam

Zam2000, Great write up, appreciate your time and effort in explaining the 722.6 transmission.

I have been doing my transmission service every 80,000 miles and keeping my fingure cross. I am hoping that I don't go through what you went on your 1998 W210 transmission issue.

Is MB used on W220 also 722.6 transmission?

cneedham810

Thanks all for the reply's. Ohlord I'm going to give that a shot and keep my fingers crossed. Your right it's my best bet before I declare it dead. It's just hard for me to pay 2500 for a rebuild when the majority of the time it drives like new.

Zam2000 thanks for the write up. That's a lot of good information. If this doesn't work I'm going to research all that deeper but I hope I don't have the same problem although it looks like theres a good chance I do.

The problem I'm having is that this is a 2000 E320 with 127k on it. I don't know if it would even be worth rebuilding the transmission. But hopefully ohlord has the right answer!

zam2000

The problem with ZF-722.6 happens mostly on C, E, CLK from 98 to early 2000. Later 2000 on have this resolved.

From what I'm told, all W220 have trans w/ upgraded part.

You might want to ask them if they're going to work on planetary gear if they quote you $2500. That part by itself cost almost this much. If unfortunately your trans go out, and you plan to keep the car for long, might want to consider dealer option.

ProV1

incredibly useful & insightful post. thank you