mis3

I thought it is the alignment of the pins. It took my indie a few minutes just to replace this connector.

Rudeney

It's a keyed fit, so I can imagine alignment of the electrical pins would come into play. I've not done this myself, but it seems every time I read posts about someone else doing it, they mention how hard it is to get the bushing inserted. I just figured that after all the leaking, they probably went overboard on the o-rings.

tw2

It is easy to align. There are 3 exact guides around the edge and 2 other approximate guides in the middle. These have to be aligned before the pins even touch the holes. It is seating the O rings which takes a lot of force. With the new design it should be impossible to bend the pins without destroying the whole plate first.

tw2

It went out of gear again today. It seems to be going into second gear late (ie in 1st for too long) and staying in second for too long before changing to third. Also changed back inappropriately to second a couple of times too. I am now hoping it is something like the second gear solenoid but I don't know exactly how these things work.

I guess the dealer will tell me tomorrow when I finally get the codes read. I will post them up after work.

mis3

Sorry that the problem came back.

I had similar experiences 2 years ago and the cultprit was the conductor plate.
For your reference, Below were the codes pulled by my indie:
P2203 The internal electrical of component Y3/6n3 (speed sensor 3) has filed.
P220A The speed comparison Y3/6n2 to Y3/6n3 is implausible.

tw2

Thanks for the info. Unfortunately it doesn't look good. P2500

xsever

I showed the scan to my friend who is a mechanic working for the local MB Stealership and he said the following:

Put the car in Drive, apply the parking brake, press the brake pedal all the way, and step on the gas halfway for 5 seconds maximum. If the RPM rises above 2000, this means the transmission is slipping and you need to do the following:

Remove the valve body and look for the hole where the input speed sensor is. K2 is present there so inspect the teeth of K2 and try and rotate it with a screw driver gently. K2 should not rotate at all if it's ok. He is saying if the teeth are damaged, you should have had metal particles in the oil from when you changed the ATF the first time.

If there's no slipping, then just check the input speed sensor and see if it's damaged.

tw2

Wow thank you very much for that. I did the valve body and changed the conductor plate last weekend. ATF was definitely clear. Absolutely no metal particles in the pan and the magnet looked exactly the same as I left it. Is the input speed sensor one of those two on the conductor plate?

I couldn't work out how to do thumbnails but they actually copied the whole report for me if it helps?

tw2

Mercedes were to get a quote to me yesterday but hopefully it will come through on Monday. I am hoping with the lack of metal debris it means the hard parts are all fine and it is a case of pulling it apart and replacing whatever seals/clutch packs etc are required. Otherwise I might be buying a second car and hunting around for a used trans later in the year.

tw2

Here is the proposed parts list from the dealer. 10 hours labor, approx US$4000 total.

N/STOCK DRIVE SHAFT (SNG)
N/STOCK SEAL RING (SNG)
N/STOCK GUARD PLATE (MBNZ)
N/STOCK SEAL RING (MBNZ)
N/STOCK PISTON (SNG)
N/STOCK DISC SPRING (SNG)
N/STOCK SPRING RETAINER (SNG)
N/STOCK SEAL RING (SNG)
N/STOCK SNAP RING (SNG)
N/STOCK DISC SPRING (SNG)
N/STOCK OUTER DISC (MBNZ)
N/STOCK INNER DISC (SNG) x 6
N/STOCK OUTER DISC (SNG) x 5
N/STOCK DISC (SNG)
N/STOCK SNAP RING (SNG)
N/STOCK ANNULUS (SNG)
N/STOCK SNAP RING (SNG)
N/STOCK AXIAL NEEDLE RLR BEARING (SNG)
H0802 GASKET
I7 TRANS OIL FILTER
C1 GEAR OIL
H0804 TRANS ELECTRICAL PLUG
H0102 COVER
H0804 LOCK PIN
N/STOCK GASKET KIT (SNG)

DanielFD

Thats a bit much, if your thinking about paying that much just buy a completely new trans and install it yourself. its not that hard if you have the right tools.

tw2

Unfortunately being a small country we tend to grossly overpay for car parts, kind of like Canada but we are 1/20th the size. I suspect a new transmission would be $7-10k here.
I would definitely be able to change transmission myself but I need my car ready, reliable and driveable in a month for a long trip and I don't have the time to look at alternative options. I have yet to learn more about the transmission but I am hoping that this parts list will essentially update the seals, parts known to fail and give me another 100,000km from it.

gixxerboy

I'm assuming they got your transmission dissembled to be able to give you that parts list?
Also at least in america, you can get allot of those parts together in a kit. Its allot cheaper then buying each part individual as they have it

tw2

No, they don't want the car until the parts have arrived. No tear down yet. Just about all the parts are 10 days ex-singapore warehouse. I don't think many parts are kept in the country so my guess is they want everything they need in the hope that nothing will need to be ordered during the rebuild.

I am new to auto transmission problems, the closest I have been is replacing a clutch and throw out bearing in a manual. Would it be correct to assume that if there is no metal in the fluid/pan/magnet then the only reason the drive shaft ($1000) which looks like the K2 "housing" to me would need to be replaced is from scoring the bearing surfaces?

I would normally approach a problem like this by pulling the trans myself and going through it with someone knowledgeable. Unfortunately I need my car working in a hurry so it is a combination of taking it to someone I trust to do a good job while trying my best to understand this enough to not get ripped off.

Any info or advice you can give me would be greatly appreciated. What parts would you think should at least be inspected in a 100,000 mile tear down? and what should be replaced regardless of condition?

gixxerboy

They are making allot of assumptions since its not disassembled.the k2 housing is a drum, the shaft presses into that. You really cant remove the shaft so you replace both at the same time, when i buy it comes together not separate, its part of the drum.
From what you are describing i would be surprised you need the drum, its possible but no way to know unless its disassembled. Typically new friction and the piston would be fine.

I'm building a 722.9 now thats getting more parts than yours, the front pump failed and the part cost me over $500 and that job is $4450.

I think your getting taken

tw2

My understanding is that if the drum was damaged the whole transmission would be ruined from metal on all the bearing surfaces which means new or used transmission?

What would be the reasons that only the K2 drum would be replaced? Just damage to load bearing surfaces? Or are there other reasons.

Would tear down be the only logical next step? The only diagnostics so far are the readings from the ECU above. Again thank you for the second opinion. I don't mind so much their exorbitant labor charges and parts are generally expensive and unavailable here but I really want to avoid changing unnecessary hard parts and on the other hand, not changing other wear items preventatively that could fail in the near future.

gixxerboy

if the drum was damaged you def do not need a whole new transmission, We get cars all the time with metal in them and rebuild them, but even by that anaolgy, why isnt the torque converter being replaced? Metal would have gotten in there too and you cant completely flush it out. I would want a new converter anyway with having the trans done.
The drum could need to be replaced for lots of reasons, its burnt from to much heat. Its physically cracked or damaged. But there in no way to know unless its disassembled.
The bearing are like the bearings in an engine, they are not roller type. You just replace the bearings themselves or individual ones that need it.
Yes tear down would be the next step. It def, has an internal failure. But that is the only way to know what parts are needed. His parts list just makes no sense.

gixxerboy

this is similar to what he is talking about, except this is from a 722.9 7 speed

tw2

Thank you for that. I have watched a couple of 722.6 tear down videos on youtube so starting to understand the basic anatomy. What things would you usually replace on a mid to high mileage transmission regardless of the failure? You have mentioned the torque converter. Any specific bearings or seals? Sprag bearings? Should the dozen or so clutch discs be replaced in each clutch pack or inspected and only replaced if necessary?

gixxerboy

i replace every clutch disc, they are wear items, i replace all of them in every transmission rebuild.
all seals and gaskets and o rings , pump bushing and filter of course.
yes, i would replace the torque converter also
as far as the sprag and what else, that is where the internal inspection comes into play.
every transmission varies on what else i would replace, there are common causes of failures , so even if that part hasnt failed it will get replaced .

tw2

Thank you very much for your help. That all makes perfect sense.

Is their parts list simply all the components for K2? plus the usual filter, pan gasket, electrical bush.

gixxerboy

Thats what it looks like, with out more detailed description or parts #'s. but it looks like everything for the k2, all the snap rings and disc. It looks like they are fixing that and thats it. To me thats not a rebuild. Its a patch job, im sure it will work after, just not getting a rebuild, And it also looks like they are just replacing everything from that assembly to cover themselves when im sure you wont need every single part from the k2 assembly

tw2

The car is in at the moment, hopefully will be back from Mercedes early next week. They replaced all of the K2 assembly but are also replacing all of the friction discs in all clutch packs and inspected the entire trans. They will flush the torque converter, cooler and lines and reset the adaptations. They agreed to put a 2 year warranty on the transmission too all for the original quoted price. Might be pricier than taking it out myself and going to a trans shop but I am happy with the proposed job (after lots of correspondence).

gixxerboy

thats better, glad it worked out like that.

Rudeney

I am very surprised a dealer is doing this work. I just go through replacing the front fluid pump in my 722.9 and while doing the job, I discovered a cracked bearing on the front of the K2 annulus (drum). I tried ordering the part and was told "none in the USA at any dealer". My local dealership parts guy told me that they do not stock any internal transmission parts as they simply don't do that work - they replace transmissions with new or rebuilt units.