Transmission Reverse Gear noise
 

Sleepwalker, I would like to help on your 3 STARS, or anyone trying to elevate their star status. I have several Mercedes one is a 95' S320 120,000 troubler free miles. Unfortunately I have some reverse gear noise when backing. I have always changed trans fuild *dextron III, every 60,000 including filter and draining torque converter. Forward gears are as quit as they should be in a Mercedes. It sound like my old ford truck backing up, that lasted over 200,000. Could it be the pressure cable is out of adjustment ? It's only been happening the last 10,000 I am finley noticing.
thanks for any help :)

RE: Transmission Reverse Gear noise
 

you got me there sanddog. but it happens to be my favorite job. the only thing that i am not certain is the type of noise that you hear. i have an experienced ear but now i have to rely on hunch.

i know that you have good understanding on technical things as with the other regular poster here, and that will save me energy tapping the keyboard.

* excessive play in multiple disc brake. this is located in the front part of your transmission, so the good news is that you don't need to pull everything inside out. but the bad news is you have to remove the transmission :D

** externally toothed disc carrier of clutch 1 fouls the plunger of brake disc for reverse gear. you also need visual check for it.

*** adjust play to specified value of 1.5 - 2mm or replace the internal discs. the internal discs as you know is of two types. externally toothed which is made of steel with different thickness (remember that thickness!) internal toothed is made of .... fibra or asbestos or somethin.:eek:
that adjustment is the distance between the plunger and the spring plate (remember the position of that spring plate! it's concave/convex (how do you say that in english?)

anyway, if you found those components without scratch or wear-out pattern, then proceed to this:

****front planetary gear. seems this one cannot repair, but only replace.
***** check also the plunger on B3 or brake disc for reverse if the lip seal is leaking or bad. it is a big O-ring. easy to check because this is the first part that you pull out (the cover).

:( am tired writing. ask me again.

RE: Transmission Reverse Gear noise
 

Sleepwalker, THANKS for the *essay. I really appreciate our insight,however
I don't have that kind of time to R/R a trans. It's not in the stars. I am trying to add your forth star. Well...OK anyhow to double check your hearing you speck of?. Imagine two gears not quite in sink with one/another and loose shims.(still on the quit side). What ?? would cause
a good tight transmission to develop a problem like this. I can't sneak up on anyone in reverse, they have that look>>> ( I would never own a Mercedes, my old Jaguar is so dependable with it's fuel leak's) I can be very easy on reverse, how much time do I have Doc..? thanks a million

RE: Transmission Reverse Gear noise
 

a humming noise!

seems like what you hear was the gear box on rear axle.[sm=smiley24.gif]

differential. listen again.

RE: Transmission Reverse Gear noise
 

Hi again Sleepwalker, so do you ever sleep ? I sleepwalked once ! and hit may knee on the corner of tool box and fell hit my head on the bench vise. Humm, maybe it was one to many beers. Hey thanks again for the waste of your time. I wish it was the rear pumpkin, thats and easyer job.
When I'm in reverse slowly I can shaft into neutral and guess what she's as quite as the mercedes I once knew. So how long do I have Dr. Sleepwalker. I am going to get another filter put 100% sys oil in and look for metal chips in the old oil. :(:(

RE: Transmission Reverse Gear noise
 

my first response counts then.

trust me, because i'm not a salesman but a technical person.

the person who design your transmission (Mr. Schultz) happens to be my teacher too everytime i go down in Stuttgart for training.

changing oil cannot solve your problem because it has nothing to do with the torque converter nor the valve body.

RE: Transmission Reverse Gear noise
 

I know....., I was mostly curious if metal droping were present. And I must say we are lucky to have you.
Thanks and please stay active on Mercedes Forum.[8D]

RE: Transmission Reverse Gear noise
 

sanddog, maybe the mechanics have already checked the presence foreign object inside the oil pan / filter when they change your ATF. if they did not open the oil pan, batter have it checked.

you can save time and money now because the circlip lock on the B3 piston hopefully didn't come off yet. if this one does, the damage will be more.

thanks for the compliment [sm=smiley9.gif]