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Discussion Starter #1
Hey guys, need your help. I just bought a GLI and pretty much things are going well but when I back up, I'm hearing a moan from the rear of the car. I had the brakes looked at and they didn't see anything and the pads still have 8/32nds. It's only when the car goes in reverse. Any ideas?

Thanks!
 

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maybe your syncros ?

Get a little more info, so I understand a little better.

What do you mean by a "moan" ?
 

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Discussion Starter #3
It's like a high pitch moan. Like it's not quite a squeak. It makes the noise even when the car is in neutral so I don't think it's the synchros...
 

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is it like a winding noise ??
 

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if it's a winding noise. No need to worry..

Here is my explanation

Manual transmissions use mostly helical gears, but reverse is a special situation that requires a different type of gear - a spur gear.

The gears that make up the forward gear ratios are all helical gears. The teeth on helical gears are cut at an angle to the face of the gear. When two teeth on a helical gear system engage, the contact starts at one end of the tooth and gradually spreads as the gears rotate, until the two teeth are in full engagement. This gradual engagement makes helical gears operate much more smoothly and quietly than spur gears. Also, because of the angle of the gear teeth, more teeth are in engagement at any one time. This spreads the load out more and reduces stresses.

The only problem with helical gears is that it is hard to slide them in and out of engagement with each other. On a manual transmission the forward gears stay engaged with each other at all times, and collars that are controlled by the shift stick lock different gears to the output shaft (see How Manual Transmissions Work for details). The reverse gear on your manual transmission uses an idler gear (the large spur gear visible at the right side of the picture below), which has to slide into mesh with two other spur gears at the same time in order to reverse the direction of rotation.

Spur gears, which have straight teeth, slide into engagement much more easily than helical gears, so the three gears used for reverse are spur gears.

Each time a gear tooth engages on a spur gear, the teeth collide instead of gently sliding into contact as they do on helical gears. This impact makes a lot of noise and also increases the stresses on the gear teeth. When you hear a loud, whirring noise from your car in reverse, what you are hearing is the sound of the spur gear teeth clacking against one another!
 

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Discussion Starter #6
I just don't understand how this is the case when if the car were to roll back without being engaged in any gear it could be the synchros. Like when I inched back at the light today, it whined for a split second.
 

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try going in first then into reverse. when i reverse, and ONLY when i reverse and hit smoothly on the brakes theres a little tad of squeeking. had the car for more then a year and ive had no problem with it.
 

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Does the moan sound like its from right side or left side? Does it make this noise while the car is @ a stand still
 

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Discussion Starter #10
It does not moan unless the car is moving in reverse. It never makes the noise standing still.
 

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It could be your brake pads.

You said you have pad left, however your brake pads will drag just a slight amount all the time. Because 99% of your driving is in the forward direction they get a groove and wear pattern of forward driving.

When you go into reverse you are going against the grain of the pads causing odd noises. Mine do it all the time in reverse, especially if it's damp out.
 

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Mine are like a squeak.

To isolate if it is or isn't the brake pads just apply some brake pressure when traveling in reverse. If the sound goes away then its your pads. They should only make the sound when there is light pressure against the rotor.
 

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yes same for mine traveling in reverse it heppens i think its just the larger rotors in the rear that like to sing
 

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My car makes a squeaking noise like a piece of metal sliding across a vinyl floor or something similar. I replaced my rear rotors with cheapo's that rust easy and that's the reason mine do that in reverse.
 

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My car sounds like a whining cat being put to death slowly when I am in reverse, but it has sounded this way since it was a year old and my friend owned it (now it's almost 14).

I've always just thought it was the way the transmission reverse gears sounded.

And going backwards in neutral creates some other noises that are brake pad related, i guess -but it is not actually a problem

I have a really long driveway to back out of every morning now -I will pay better attention tomorrow and see exactly what I hear in Neutral.
 

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So what's the verdict?
My car in reverse or in neutral going backwards stays at 2000 rpms and "whines" really loudly. Didn't hear any brake noise this AM but I have in the past. The gears are noisy but nothing compared to the motor at 2k whining.

Im not sure if this is normal.

I had to catch a plane this morning and was in a rush. Tomorrow I will really get some better info.

One thing is certain -I doesnt sound healthy going backwards.
 

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i wouldnt be worried if theres no tranny oil leaking grinding or hard or rough engadging... if so id set up an appointment with someone that has experience with these trannys because they can be very penpermental (i heard)
 

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Discussion Starter #20
It's definitely the brakes. Something is up with the rear. Could it be the calipers sticking? Think the arctic air is playing a part.
 
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