Marble noise in the transmission 88 560SL
 

Gentelmen

A few days ago I was driving to work at about 65 MPH and suddenly a noise sounding like marbles from inside the transmission occured. When slowing down I noticed the noise frequency and amplitude tracked road speed only. There was no observable change in the vehicals performance characteristics. At first the noise pretty much disapeard below 10 MPH. Now I have to get up to about 60 to get is started and it will remain until I reduce speed below 40 MPH.

Of course when I got it home and put is on jacks, it wouldent happen at all. I did notice what appeared to be an out of balance condition from either the wheels or drive shaft when I was running it on the jack stands. Tires are new and recently balanced.

I have a couple of questions

1) Is the transmission governer removable with the tranny in the car and might this be the problem.

2) Is there a way of knowing how much drive shaft imbalance is too much and is there a balance proceedure.

3) Does anyone have any other ideas what of what could be wrong.

John Roncallo

I would guess it is the shifter bushing. Many times when it wears it sounds like you are dragging a tin can behind the car.

Sorry

I cant understand how a shifter bushing can make a noise that increases with road speed. Please clarify. This is an automatic transmission car.

Thank You
John Roncallo

Have you tried to shake the wheels to rule out the wheel bearings? Thought I'd mention since you're noticing some un-balanced wheel moments (and had balancing done recently)

Frank.

The reason I suggested the shifter bushing is because I had the same problems (with the exception of the rough handling) and that is what it turned out to be. Evidently the vibrations from the road (which did get worse with speed and decreased when slowing down) caused a resonating effect when the transmission and shifter "rubbed" - causing a resonating effect (sound like marbles or tin can being dragged under the car).
I would think a worn ball joint or wheel bearing sound would eminate from either the front or rear of the car, not from the transmission.

I have not tried that. Nor have I looked at the CV joints. But I will put it on the list of things to check.

Thank You
John Roncallo

The noise is eminating from the console. The only bushings I can think of are the one at each end of the shift linkage rod and I'm assuming there is one in the shifter itself that the shift lever pivets on. Are one of these the bushings you are speaking of.

Thank You
John Roncallo

Mine was the bushing where the shift linkage actually attaches to the transmission and the bushing where it attaches to the shift lever itself. They are cheap and an easy fix. I am sure if they have not been changed over the years it is time. Mine is a '90 420SEL and it was changed two years ago.

That would be really good news. I'm still not too optimistic but I will be under there this weekend.

Thank You
John Roncallo

Good luck. I sure hope this is the problem - sounds exactly like what mine did. I don't know how easy it is to change on your's but mine was a peach!

No luck

The bushings are fine. Today I was able to get the noise to occur with the car on jacks. The trick is to warm it up good before jacking it up. It unfortunatly appears to be something inside the transmission. It is still hard to tell. Its very loud underneath the car with the wheels running at 65 MPH. I still have some hope that it is the drive shaft center bearing, but the noise does emminate from the aft end of the transmaission. I think I have a bad bearing.

Thanks
John Roncallo