deru

Good afternoon Mercedes enthusiasts.

I have a 2005 e500 sedan with 170k miles and a 722.9 trans. This car was a rebuilt salvage title that i bought 5 years ago at 109k miles and havent had any serious mechanical problems.

The transmission started slipping the other day between 1st and second gear. It was driving fine until i stopped to get gas. After i was done fueling up, I turned the key in the ignition like you would normally do to start it and the engine started turning really fast but it didnt fire up. i had to take the key out of the ignition in order for it to stop making the noise.I shut it off for 5 seconds, tried again and it started fine. Once i pulled off thats when i notice the trans slightly slipping. I say slightly because if i drive it really gently, I dont experience the issue. My initial thought was low trans fluid and the weird start after fueling was a coincidence. I hooked up a scanner tool to it and i got code P0730 (incorrect gear ratio). I erased it and drove it but still had the same issue.

I took it to a transmission shop that seemed to be knowledgeable and have experience working on the 722.9, all the proper diag scanners, etc... When i picked it up, he said i needed a new valve body, clutch packs and they would need to rebuild the trans. It started sounding fishy to me. I asked him how they checked the fluid level and he said that the trans is sealed for life, there arent any leaks so it cant be low on fluid and never needs to be serviced. He also told me they dont have any Mercedes diag software and just use a snap-on scanner. He said their scanner pulled code P0894 and cleared it.

That was yesterday. Ive been driving it and neither code has come back since but still get that slip unless i drive it like an old lady (no offense to any old ladies reading this)

I read on this forum and confirmed with the dealer that you do indeed service the trans and mine was by the previous owner at 60k. Dealer said they would diag for $175 -_-

So i guess my questions are this:

1) Does anybody think the weird start and the trans issue are related?
2) Does is sound like is just needs a trans service?

Thanks. I look forward to hearing your answers!

kaane

Here is what WIS has to say about this code. Basically there is an issue inside the valve body. Either one of the solenoids is bad, spring failed or there is contamination. Possibly a bad harness, but unlikely. Easiest option would be to get a new valve body.

Complaint:
Target gear is not reached, transmission in mechanical/hydraulic limp-home mode

Fault code:
055 I5I P0 730
Possible cause / Remedy

• Oil filter not assembled / Assemble oil filter
• Wiring harness damaged, short-circuit, chafing mark / Check wiring harness to ground.
• Shift pressure control solenoid valve (Y3/6y2) blocked (foreign matter) / Replace solenoid valve.
• Control, shift or command valve blocked (foreign matter) / Check slide valve for end position and ease of movement, free off if necessary.

• The spring in the control spool pressure regulating valve may be broken / Replace spring (part no.140 993 58 01).

https://www.mbdirectparts.com/oem-pa...e-220270310680

$700 for a new reman valve body.

deru

Kaane - Thank you for the info. That's really helpful and gives me some direction. Hopefully you can answer some follow up questions. When I click on the link, theres no image available.

A) Do you know if that valve body also comes with the conductor plate? From a couple videos I saw, the valve body and the conductor plate were separate. The valve body had the springs ,etc...and the conductor plate had the solenoids and TCU built in it.
B) Do you know if I can replace one and not the other? Ive read that with the 1st generation 722.9 (which I have) you have to do both.
C) If it does come all together (valve body/conductor plate with TCU) will I have to get the new TCU flashed with the info from the old one?

Thanks again!

kaane

A) it will be a complete unit with valve body and TCU. Can't buy them separate for the 722.9 early models.

B) Not from the dealer, you could hack it, but it's a pain. You would need to find someone to either rebuild just the valve body and use your TCU, but if the TCU has issues that won't fix it. Replacing both is only safe way to make sure the whole assembly works.

C) You will need to get it coded, they come locked I think and need to be unlocked to work correctly. You just need a factory scan tool or similar. You don't need to copy any data from old unit since the new one will come calibrated.

deru

Kaane youre the man.

Last question i think....I feel comfortable removing and reinstalling the valve body/TCU but i havent found a video or information online on how to fill the trans back up with oil. From what ive seen, it almost looks like they use a pump to inject it in there. Do you have any feedback on that?

Thanks again!

kaane

Watch this video for steps to remove the valve body, you can skip the tcu removal part.


This video is good to show you how to fill it up. You will need a special adapter and a fluid pump.


Here is the adapter


Here is the pump I used to fill mine.

kaane

Also if you are going to buy the valvebody call a dealer and give them your vin to verify the part numbers. I used mine, but who knows there are always variations.

deru

Hell yeah. Thanks!!!

cetialpha5

And also replace the pilot bushing. You can also buy those parts online, places like www.oediscountparts.com will discount off MB list price and has free shipping. You can give them your VIN when ordering to make sure you get the right part.

You can also get the transmission fluid Shell ATF 134 from a Shell distributor. About $60 for a case of 12 quarts, way cheaper than the $20+ a quart or so from the dealer.

https://www.shell.us/business-custom...r-locator.html

You'd have to check each distributor in the list as they only list headquarters and some distributors have multiple sites.

arto_wa

Here is also a link to a 722.9xx service thread that has been running for over 7 years!
Lot of useful info for a DIY service.

https://mbworld.org/forums/c-class-w...ce-thread.html

cMazara

are you sure it's a 722.9 and not the 722.6?

Thought the 722.9 was available on the facelift model only.

konigstiger

E500 has 722.9 since 04.

BenzPR

Good morning! I know that this is an old thread but did replacing the valve body/conductor plate resolve your issue ?

I’m having the exact problem with the exact codes P0730 and 0894

arto_wa

It looks like the last time he posted on this forum was on 01-29-2018

Apparently OP's car went fro 60,000 miles to 170,000 miles without transmission service and developed a transmission slipping problem!