20vt4 whining noise from haldex/diff

Mcfly91

Active Member
May 4, 2017
6
0
Sweden
Hello, I have a problem with a whining noise coming from the rear axel of my Leon 1m 20vt4. It's a whining noise that start very suddenly at about 40km/h (25mp/h) and up. Doesn't matter if I accelerate or deaccelerate it's still there, but if i drop below 40km/h (25mp/h) it stops suddenly. It does not increase in volume but rather in frequency together with the speed. I noticed it for the first time as i pulled a trailer behind my car. The whining is constant as you maintain a constant speed but it has "dips" in the frequency like if the noise comes from something that isn't 100% even. I haven't heard it during the cold wintry season, but as soon as the temperature outside hit positive degree (Celsius) it started to make this noise again. I did a total wheel alignment on the car a year ago just to find that my rear axel have got too much positive toe-in angle while my front wheels have perfect toe-in and i'm starting to suspect that either my rear diff or haldex is suffering from too much heat because of the huge difference in friction or force between the 2 axels. I do not suspect the pinion gear in the diff since the sound starts so suddenly (it's not the kind of sounds that lies dormant and kind of creeps upon you =P). I changed fluids in both the haldex and rear diff during the last service 10000km ago and the rear diff was treated with Slick50.

Anyone having a clue of what it could be?
 
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