td4 rear diff noise, no noise at all now that shafts are removed!

inishowenfreelander1 · Feb 11, 2016

Being a dumbass I hadn't checked oil level in rear diff in ages.. Started making a noise after a long journey one day. Syringed out as much old oil as I could and refilled with new stuff.. Sounded a lot better right away but still a slight noise.. Took off prop shaft and vcu tonight and now there is no noise at all coming from diff.. Is this just because there is no drive going to it..? As all parts inside diff will obviously still be moving while driving 2wd.

GrumpyGel · Feb 11, 2016

The bits may all be moving when 2WD - but not under hardly any stress. As soon as the props are installed its under much more stress, even in a straight line with good VCU and matching tyres.

inishowenfreelander1 · Feb 11, 2016

GrumpyGel said:
The bits may all be moving when 2WD - but not under hardly any stress. As soon as the props are installed its under much more stress, even in a straight line with good VCU and matching tyres.

I'm thinking it is diff, tell me this. Should front and rear shaft turn together or independently when out on the ground.?

GrumpyGel · Feb 11, 2016

You mean when the shafts are out of the car and on the ground? There will be the VCU joining them. If you pick one up and turn it, the other will turn with it. If you jam the other end and try to turn by hand it probably 'won't turn' - but if you put a lever on it it should turn very slowly. Basically you're doing a 1 wheel up test or workbench test on the ground. The VCU should allow 'limited slip' between the props, but if you try to turn by hand given the small leverage of holding the prop it will appear 'joined'. Of course if the VCU is knackered, you may need a very long lever indeed to get any shift it.

inishowenfreelander1 · Feb 11, 2016

GrumpyGel said:
You mean when the shafts are out of the car and on the ground? There will be the VCU joining them. If you pick one up and turn it, the other will turn with it. If you jam the other end and try to turn by hand it probably 'won't turn' - but if you put a lever on it it should turn very slowly. Basically you're doing a 1 wheel up test or workbench test on the ground. The VCU should allow 'limited slip' between the props, but if you try to turn by hand given the small leverage of holding the prop it will appear 'joined'. Of course if the VCU is knackered, you may need a very long lever indeed to get any shift it.

Fair play to you for understanding what I was on about, lol.. Great info thanks ..

GrumpyGel · Feb 11, 2016

You obviously can't really test it like that. You need to either put it on a workbench and find some timings that should be expected (but I don't think there are any publicly available) or with the props installed on the car just do the 1 wheel up test - you do need a 32mm socket to do it but there's expected timings on the VCU testing thread here (together with a lot of other talk!).

td4 rear diff noise, no noise at all now that shafts are removed!

inishowenfreelander1

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