I have a 2007 GL450
a few years back I had to change the conductor plate in the transmission.
i don’t know if what’s happening relates to that and I realize that somebody recognizing symptoms in this video is a shot in the dark but maybe I’ll get lucky

the buzz you are hearing is from a wire that’s not grounded but it amplifies the sound of the weird shifting.

any help would be appreciated

 

I knew this would be a shot in the dark but I didn't get any responses...nobody has any experience with their car revving up like this?

 

How many miles / yrs on your fluid?

 

ive only had the car 3 years....in the first year I had to change the conductor plate which I had to change all of the fluid so I'm sure that the fluid may be due to be changed

 

Every 40k the 7g gets new fluid.

 

I'm not familiar with the sounds captured in the video. I first thought that your Airmatic compressor might be loose off its mounts. I recall a thread mentioning that it engaged at 18 mph and again at 26 or 41? Those speeds corresponded to trannyup/down shift points. I can't recall the second number hobestly. Then looking at the speeds in the video, I am not sure it's really the compressor moving wildly and banging into something. But I think it's worth taking a look at it.

 

Yeah we determined the compressor doesn’t work at a standstill a while back. There’s too much background noise to hear what’s going on in the video but from the needle movements I’m not seeing anything strange.

 

While you changed the conducter plate did you change the Orings on the solenoids in the valve body? The lower Orings are probably the number 1 transmission issues right along with the conducter plate and speed sensors.

 

I'm pretty sure the answer to that is no. What are the symptoms of bad lower o rings?

also what are symptoms of bad speed sensors? I haven’t heard of those being an issue

 

I'd be interested in replacing those o-rings proactively the next time I do a fluid change. Do you have any more info or references on where to find them?

 

when the vehicle speed sensor on the valve body (not the wheel speed sensors on the axles) is unable to read/send a speed signal through the conductor plates due to dirt and grit contaminated fluid; it trips a code which puts the tranny in limp home mode.

you’re locked in 2nd gear as long as this code persists.

if you wanna post up another video of said condition with no background noise perhaps we can offer a better remote diagnosis.

 

Ok here is an example what I went thru recently.. A couple of hard down shifts from 2-1 than limp mode. only code was a very uncommon 0893.. hydraulic issue possibly throwing 2 gears in at once. I spent hours calling dealer shops and searching the forums . I finally decided to drop the valve body and inspect . I run the top of the line Amsoil signature tranny fluid so everything was clean.. but B1 solenoid had the bottom Oring 1/2 missing . B1 is the brake solenoid that activates between gear changing .
As the valve body comes up to pressure fluid can leak past the solenoids Orings causing erratic shifting. I have changed the Orings in 3 valve bodies and the bottom rings have all been weak. My 2008 GL550 has 130k miles on it.
Ok Cobra Transmission parts in Florida just got stock back in. $26 or so for the kit. Don’t forget to buy the 2 orange electrical connector Orings also.
I am going to put some packages together soon and sell them on my son’s ebay site where he sales R129 parts. OK I hope this helps… I spent pretty much a whole week searching for the proper Oring grades and sizes BECAUSE COBRA was out of stock . I went with
FKM V75 ( a high grade viton top and bottom Orings)
I looked into Cobras and they are Viton on the bottom and poly on top???
I believe or educationally guessing that the early MB Blue Orings on the bottom are a cheaper grade and can’t take the cold weather as well as the V75’s. V75’s go down to —20F and some early Vitons only go to +5F… my tranny went down on a very cold day.
Than of course to top it all off MERCEDES only sales the complete solenoid for well over $100!!! No Oring only sales. ok take care Bill
Don’t forget to clean the screens and bottom of the insertion area with a magnet. plugged screens can also act up the shifting patterns.

 

If you list that kit, I'll buy it. Our GL has some funky shifts occasionally so it would be nice to baseline by checking things like o-rings. Are all of these solenoids in the valve body, or are they elsewhere? I've seen people pull valve bodies in videos before but haven't delved past the filter, myself, so it's a gray area.

 

Sheesh. Wonder how many dealer diagnosed contractor plate issues might actually have been just this.

 

Add me to the list of people that will buy that kit. My 2008 GL320 has some odd shifts lately (about 8mos after a trans fluid change) almost like it hesitates on whether or not to grab an up gear. Happens only on mild acceleration from ~25MPH to ~45MPH

 

Ok for those that have not replaced or removed a conducter plate or solenoids here are a few pictures . The solenoids have the black and greenish blue caps. Remember to mark the solenoids and replace them in the same location. The 10 aluminum bolts holding the valve body are also a one time use bolt like so make sure you have tranny pan bolts and valve body bolts on hand ( valve body bolts are approx $30). I used an egg carton to hold the solenoids while I cleaned up the valve body. I did NOT split the cases open with the 14 check ***** but I did SLOWLY remove the 14 shift spools and springs inspecting for broken springs or stuck spools/pistons.. mine were all clean because of the Amsoil. Pay attention to all the torque values.. solenoid spring clamps , conducter plate bolts , side covers for pistons/spools…
I used cheap roasting pans from the dollar store to hold the valve body while I removed parts.

 

I have maintained 4 SUV’s for years..2005 ML500, 2006ML500 7 speed, 2008 GL550 7 speed and 2009 ML350 7 speed. By far the 2009 shifts the best.
I have a pile of tranny gaskets from all the fluid changes because in my belief it is the weakest link that we can maintain ourselves. I have changed at least 15 fluid changes anything from original MB, Fuch 134, Shell 134…. the last few have been Amsoil signature .. with unreal results . I ran my GL550 45,000 miles and it was red and spotless . I would highly recommend that anyone trying to maintain at least try it once. Once you buy the low cost membership the 2.5 gallon can cost $125… that’s $12.50 a qrt. The cheapest stuff was shell around $6 a qrt and it always looked brown and horrible no matter how many miles I put on it.
ok some more of my thoughts . Also just bought Wix tranny gaskets and filters from RockAuto and they looked real nice for $25 per set.
Back on valve bodies…
My GL550!has a 220-270-1906
2009 ML350 has a 220-270-2306
the new replacement for them from MB is 220-270-2706
I have read about different upgrades aftermarket drilling out certain spools etc… I believe the newer valve bodies have those features. The difference in the two I listed is quite different ..