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-   -   Transmission noise in reverse? (http://www.peachparts.com/shopforum/tech-help/11868-transmission-noise-reverse.html)

roas 12-18-2000 09:53 PM

I just purchased a 92 500E recently and am trying to sort out a problem I just discovered.

When cold, the car will make a sort of clicking noise that will increase with speed. There is no such noise in all forward gears.

I have seen this posted before, but no solution was offered and I am curious if anyone with the same problem has had it fixed? If so, was it a DIY job?

Thanks.

Mark Herzig 12-18-2000 10:22 PM

First, congratulations on your 'new' car. I had the exact same symptoms and I thought it might be the transmission. I have it at the dealers for some work and I had them look into the noise. I got a call today that the problem was some rubbing from the encapsultion panel underneath. THe tech is going to trim it to avoid the rubbing. Also, there was a piece of paper material that was causing this sound only in reverse. Tomorrow I'll get more specifics but I am relieved it is nothing serious.

roas 12-18-2000 10:35 PM

Thank You Mark,

That may be one less headache I may be able to take car of if it is a DIY job.

I really do feel that this is the most solid car I have ever driven, and plan on keeping it for a long, long time.

I now know why 500E owners are so passionate about their cars!! :)

I also think I figured out why "yhliem" has 2 500E's, one for him and one for his Wife! I won't be driving mine anytime soon if you get my meaning!:)


Deezel 12-19-2000 05:36 AM

You might also want to consider the drum style e-brake that is behind the rear discs. Listening carefully while your wife backs out for her daily drive should help you figure out whether this is the culprit.

roas 12-19-2000 10:44 AM

I'll check that out.

In the car it is hard to tell from which direction the noise is coming from.


Its close to a slight grinding, heavy rubbing sound, like something is not warmed up yet?

We shall see.

Mark Herzig 12-21-2000 11:04 PM

more information
 
I took the shop foreman a video tape of the sound as I was backing out this morning. THe sound was very distinguishable immediately to him however he did not catch it when he examined the car. I was told to "not worry"

roas 12-22-2000 11:27 AM

I noticed the sound only occurs when the car is cold.

If what you say is true and it is the transmission, I hope that one of the Mercedes Tech's who visit here can shed some light on it?

Is this a,"Rebuild time?" situation or a, "live with it" issue?


Mark Herzig 12-22-2000 11:51 AM

The noise, for me as well, was only Highly noticeable when the car was cold; such as first thing in the morning backing out of the garage. I guess one way to look at it is to live with it until you are forced to do a transmission rebuild since you will have to do a rebuild irregardless.... I'm not too sure there's a prudent middle ground.

mbdoc 12-22-2000 12:50 PM

Does the car have to be moving or does the trans make this noise when reverse is engaged? If the noise happens w/o moving then the trans needs the reverse clutches replaced; this is a result of the reverse piston hitting rivets on K2 clutch pack!

Mark Herzig 12-22-2000 02:07 PM

In my situation the car has to be moving in reverse. Just having the car in reverse w/o moving seems OK.

roas 12-22-2000 04:02 PM

M.B.DOC,

Same for me. The car has to be moving in order for for the car to reproduce the sound. If you speed up, it speeds up.

Must be in the driveline some where? This weekend I will make some time to jack the rear of the car up, put some stands under it and start her up. I'll have another person shift it into reverse with the foot on the brake and then slowly let the drive-line start moving.

Now with me UNDER the car I should find the problem! Lets hope I am not drawn the the transmission!



[Edited by roas on 12-22-2000 at 04:09 PM]

Benzmac 12-22-2000 08:43 PM

Most of the time, these noises should be diagnosed by a tech. I have heard them come from the lug bolts hitting the brake shoes in the rear and from the piston in the tranny as Doc said.

Just know your tech!! This could be easily misdiagnosed.

Deezel 12-23-2000 08:16 AM

Danger Will Robonson!! (And Ross). The last sentence got jumbled in your excitement and I am not sure what you meant. As the self appointed safety czar, I am concerned that you are going to crawl ubder the car on jacks, with it running and in gear (drive shaft and wheels turning). I understand the personnal interest you have in this problem and your inquisitive nature, but please consider the hazards and options you have. You may have the technical expertise to perform this inherently dangerous task, and minimize the dangers, but you can not eliminate all of them and I don't want less experienced members trying this at home while their parents are at work. I guess these would be called "latchkey mechanics"?

I have posted newspaper reports of cars falling on home mechanics and killing them. I have also posted tips to work under cars safely, which I will do again just to spread the word:

ALways use good quality equipment jacks, jack stands, ramps etc. Have a flat paved area, use wheel chocks for the wheels that remain on the ground. Have a second person there that knows how to use a hydraulic jack so they can extricate you if the car falls. Have a telephone handy. Put your tool box or other sturdy thing under the car with you. This will provide breathing room should the car fall on you. All these things are very simple and easy to do, so there is no excuse for not doing it.

Now for the added risk of having hte car running. The exhaust will be hot and the drive shaft turning. The wheels will be turning. While crawling under the car you may inadvertantly touch a moving or hot object with your hand, head, leg, etc. You will probably already be nervous, hence the "jerk away" from the exhaust into the drive shaft, or similar problem. If the car does fall off the jacks, you won't die of suffocation, because the car will have backed over you! I really don't mean to preach to you, but I am concerned for you and others that might read this thread, especially if I didn't add these comments.

For alternatives, this is a good time to start really bonding with the tech and shop that will be doing all the work that you can't do. If you have a relationship with the shop, they should put it on the lift for you and let you come out and discuss the noise while it is on a lift and safe. I would guess that for an established customer, it might be free at this point, or just a minimum 1/2 hour fee. If you have not established a relationship with any shop, it is a great way to really figure out who you want to work on the car when it is needed, even if this problem turns out to be a simple home project!

You have a wonderful car, and I hope to see you in it on the road someday! Good luck and let us know what the problem is when you get it figured out!

Season's Greetings!

roas 12-23-2000 10:51 AM

Don't worry Deezel,

As the Safety Czar, I will try and reassure you. I have been working on my cars since I first had one, and believe me that car needed HELP! Many car's later, I have tryed to do as much on the car as I can, although I have never read computer codes before and am currently still trying to figure this out on the 500E.

I have always removed jewelry, wear long sleeve shirts buttoned at the wrist and tucked in, Mechanix gloves and safety glasses. The jack stands are brand new Craftsman as well as the 3 1/2 ton jack. Tire chocks are always used and it would truely be insane to work on the car on a unlevel surface unless there was no other choice (broke down). I'm on level ground though and since you mention it, I use two stands on either side, always with the jack under a central supporting structure.

I am going to either buy or make a probe for finding noises. The stethascope type with a long wand comes to mind, this is what I will use to poke around under there, I value my hands too much to stick them where they don't belong, ala drive shaft. Heat shouldn't be a problem as the car will only be running for about a minute or two.

I really like the shop suggestion as well, but the car is used during the week days and the shop is closed on the weekends.

I understand your concerns, that is for sure!!! Being in the military for 6 years and working on and around Helicopters (Electrician / Avionics Tech)), you saw some very dangerous and careless situation unfold before your very eyes.

Thanks again Deezel, and for all who have read this thread, please weigh your experience with the risks involved, getting under a car is very risky if you do not eliminate the risks or at least minimize as many as possible. This point is important!


Everyone have a Merry Christams and Happy New Year!! :) :)

deportes 03-21-2006 02:53 AM

ROAS, did you ever figure out what the clicking noise was?


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