Plse Help 97 E320 Tranny
 

HI.
i need help please.
my tranny has been doing this all the time now.
while you drive it goes into "limp mode" i think.

it seems to go into a no change mode.
if you stop and change the gear shift it will select D
and then stay in 1 st gear without a change OR it will select 2 gear only and will stay like that.

is this limp mode?
what could be causing this?
when it slects from neutral to drive it is now much more abrubt.

PLEASE HELP?????

Pulling the DTCs will provide you the fastest answer.

Has the check engine light illuminated?

Limp-home mode shifts the modulation pressure to maximum, which is why you are experiencing the abrupt gear engagement.

Several things can cause the transmission to enter limp-home ...

- the wiring harness plug adapter could be leaking... an upgraded adapter with improved seals was introduced with MY '98 production. Leaking adapters tend to throw two specific codes (I believe one is 113?) which, when seen together, can indicate a faulty adapter. The part is cheap ($10) and is not difficult to install. Visual inspection of the existing adapter can be performed if you don't have ready access to a scanner. The transmission's wiring harness enters the transmission at the right front... simply rotate the locking collar, remove the harness and inspect the interior of the plug adapter. If there is ATF present, the adapter should be renewed.

- the speed sensors integral with the electronics plate attached to the valve body may be defective or coated with so much metallic debris that a signal can no longer be detected. A new, improved plate is available. Ensure that a fluid pan magnet and new style plug adapter are installed at the time of the plate's renewal. Again, a fault code check will be necessary to pinpoint a defective plate - codes will indicate implausible or occasionally implausible speed sensor readings; ME fault codes may also be present, referring one to check ETC.6 fault codes. Removal of the valve body is required to renew the electronics plate.... not a technically difficult job but cleanliness is imperative.

THANK YOU FOR YOUR REPLY. i will look at the adaptor plugs.

when i drove the car again earlier it was fine for about 2 miles......then no changes in gears......from a stop it would have a slipping clutch feeling. stop and move selector and it would engage again.
do you know anything about the switch at the selector ?
i have disconnected the batt. and want to unplug the trans. computer briefly in the engine bay. will these clear the codes and i can then see if check engine light comes on?

thanks

hi

where is the wiring adaptor plug.? is it under the car or on top?
where is the valve body?

thanks for your help.

The part you mentioned in your second-to-last post is called the range recognition switch. It could possibly this part that is causing the problem. You need to get the car checked for fault codes as previously mentioned.

The valve body is inside the transmission, it's what you are looking at when the pan is removed.

The wiring connector, as mentioned, is at the right/front corner of the transmission case, you get at it from below the car.

Gilly

thanks guys.

i will try and get car in for scan.

after the batt. disconnect it stays in 2nd gear only and does not shift.

i will advise about the codes....
thanks
:)

hi
i pulled of the connector plug and it was wet with atf.. cleaned it out and put it back.
the check engine light is also on now. the car wont shift out of first gear. i want to get it to a shop to check codes

auto zone are close to me and can check codes?

my questions please.

the car makes a noise over 3000 rpm as it wants to change gears.....can i drive it like this?

when the codes are reset will the car reset it self and be more drive-able until fixed.

will equipment from autozone give me codes for transmission?

i am hoping it is the connector that is faulty.

thanks

do codes have to be cleared after problem is solved before it runs normal?

I find it real hard to resist the temptation to say that using AZ for such a situation would serve you right.

To think that free advice in such matters would be beneficial, degrades the intelligence of all professional technicians. It is an obvious result of all the good free advice that does float about.

You will get a small amount of data from an OBDII scanner, but any usefull analysis will have to talk straight to the transmission controller.

A good stab at a DIY repair would include replacing the conductor plate with the modifidied version (good update for all early trans) and the plastic seal coupling where the wire harness plugs to the conductor plate. I would especially advise this if any speed sensor codes were retrieved.

Unfortunately, disconnecting the battery will also reset all the adaptation values which should then be properly relearned. This is a function best done with a proper scanner also.

hi steve

not sure what to make of first 2 paragraths?

thanks for your input.

i will go ahead and get codes and do the updates.
are these parts only available via mercedes?

thanks
:D

What Steve is trying to tell you is not to monkey around with a $5000 transmission. AutoZone won't have the capability to provide a diagnosis, and you're not capable of sorting this out at home.

Take the car to an MB dealer or indie that has the capability of providing a real diagnosis of the problem. There are some "known" problems with the early 722.6 units, and only an experienced MB tech will be able to pinpoint the problem and provide a solution.

Something is amiss. Erasing the codes won't fix the problem. The codes are simply a storage of an event. You might be able to get the car out of limp-home, but why bother? If something is wrong, it will still be wrong. You could be contributing to the demise of a very expensive driveline part. You are going to have to bite the bullet and hire some expertise. On the forum, we may be able to provide some feedback as you go through the process, but an actual diagnosis is unlikely here, as we cannot touch the car.

thanks blackmercedes.
i understand....i just wanted to get somebody close by to do it as i dont want to drive the car like this. when i called autozone again they confirmed that they would only be able to do basic check.

i think it is the adapter plug as since i have cleaned it out the check engine light has gone off.
i am getting the car scanned on monday and will then get into the codes.
i hope that it is just the basic stuff like plug, adapter etc. and i hope to do this myself.

thanks for all help on this forum.
spike:D

update!

car was towed to shop.
they pulled codes and there were 16 of them. starting from code 59 upwards.

reset and cleared codes. car Wont shift out of 1st.
scanned codes and now 23 of them.

they pulled of the pan and noticed very, very fine pieces of metal.

after checking all the search items on this board relating to this topic i am not sure what to do next.
the shop is saying it needs a rebuilt.....?

before i do this is there anything else i can do?

i was thinking along the following lines as suggested on other posts:

1) replace the at wiring harness plug adaptor as i know the plug was wet with atf.

2)replace conductor plate and speed sensors.

3)OR clean the above components and reset the codes?

the shop says if the conductor plate is replaced the computor has to as well?

PLEASE HELP.

THANKS
SPIKE

I believe they are wrong about the conductor plate. If the VALVE BODY is replaced you MAY have to replace the computer, also if the TRANSMISSION is replace you MAY have to replace the computer, there is a chart they should have which will give them this information.

What they've located in the pan is really the "Y" in the road as far as if the transmission is junk. Is this a dealer that has the car?
Metal particles larger than about 1mm (chips and shavings) are usual indicators of recommendation for transmission repair or replacement. I have a book detailing what type of findings are acceptable, if you want I can quote what it says. There are also pictures but I have no scanner and they're not the best pictures anyways.

Gilly

AS Gilly is trying to say, it's tough for us to give a solid diagnosis from afar when it comes to something as complex as that 722.6.

However, you could talk to the shop about a potential repair as opposed to replacement. Talk to them about replacing the conductor plate and updated ETC (Electronic tranny control) unit. It is not unusual for there to be very fine material in the fluid, but chunks certainly can be bad news.

A faulty conductor plate will cause the tranny to go into limp home mode. Then it is stuck in gear.

If you need extensive repairs, you should talk to the Zone Rep about MB pitching in a few bucks. If you're not the original owner, you're probably out of luck, but you should ask anyway.