joe85719

2008 ML320 CDI / V6 diesel turbo w/722.9 transmission. No error codes. 180k miles

When I put it in reverse it remains in park. When I put it in drive it engages ok. Then when I put it in neutral it remains in drive. If I do not put it in drive after starting the engine for the first time, neutral is actually neutral, but after engaging drive, neutral no longer works. In summary:
- Park = Park
- Drive = Drive
- Reverse = Park
- Neutral (after engaging drive) = Drive
- Neutral (before engaging drive) = Neutral
- Lights on dash always indicates the correct mode (i.e. reverse light comes on when in reverse)

Any ideas? Some back history on this, the transmission was violently slamming in to lower gears while coasting out of higher gears (for example letting up off accelerator at 45 MPH). A few days later this problem started with reverse. I removed the valve body, connector plate and solenoids to see if maybe it was dirty. It was fairly clean but I found that all the solenoids had bad rubber seals. The rubber was completely deteriorated. One of the rubber seals was even missing. After replacing the solenoid seals and putting it all back together the violent shifting issues are gone. Unfortunately the reverse issue is still there.

I've talked to several transmission shops. They want to replace the entire transmission for about $4000 to $4500. Unfortunately due to the age, miles and condition, the entire vehicle is barely worth that. If I can't find a somewhat easy fix for this I'll have to part the vehicle out...so I'm hoping someone has seen this before.

pmercury

iTrader: (2)

did you forget to mention that you also replaced the conductor plate or is this a joke ?

A0002702600
many aftermarket brands make them cheap

joe85719

No the connector plate has not been replaced. When you ask if "is this is a joke" is that your way of saying that it's blatantly obvious that the connector plate is bad (based on the symptoms)? Are you saying that you're sure it's not any of the following:

Mechanical issue (clutches / bearings)
Bad solenoids
TCU software bug
Bad Gear Shift Module
Valve body (springs or check valves)

...if that's what you're saying then that would be awesome, and I'll swap it out and have it programmed, but I was trying to avoid throwing random parts at it, which is why I'm asking you guys for advice

pmercury

iTrader: (2)

hahaha

yes, seriously, the first thing to do is change the plate, this is the most commune problem
even before solenoids

good luck

Mr. Toad

Terribly helpful, wasn't it?

pmercury

iTrader: (2)

everybody has his own sense of humor
when you come to a major international website you adapt yourself to international humour
you are not the center of the world

pmercury

iTrader: (2)

forgot to mention

you can get them repaired too for a few hundred

MBENZTECH

It sounds as if you have a hydraulic problem..... The conductor plate most commonly will give you speed sensor problems, no communication or open circuit on different solenoids. I have rebuilt many of these transmissions. I think a better approach to this would be a complete tear down and inspection.