rear diff

Hi have asked this question on my other post as a tag along but i will ask the question as another post.
Any way took freelander out on a bit of a run and i have a whine from the rear now it is either the diff or wheel bearings it is definitely from the rear.
So i assume to check whether it is the diff or wheel bearing i will have to jack up all wheels clear of the ground or is there any other way to check that may be a bit safer as i am working at ground level thanks

What vehicle is it?
When diffs start to make noise, it's because the bearings are failing. A failing bearing will shed metallic particles into the oil. So pump out the oil for a look, if it's grey with metallic particles in it, then it's the diff at fault.

2003 freelander td4 very good point forgot about that but
I did notice the rear tyres did have unusual wear on the inner tread like dips very equally spaced on both same tyres same tread depth but having no history and the previous owner did not have a clue about cars but there is no undo play on the suspension but i will check the diff oil.
But i have the MOT in the morning so it might pick up any possible faults on the suspension it is easier to check these things on a ramp thanks

Have you checked the VCU?

They get far to stiff over time which will damage tyres as well as the transmission (IRD usually but also rear diff).

https://www.landyzone.co.uk/land-rover/tests-new-freelander-1-owners-should-do-on-their-car.312863/

Does sound like tight VCU. The rear end tries to walk then the diff or IRD disintegrate.

Do the one wheel up test as a matter of urgency.

Hi i have done OWU jacked up o/s rear hand / brake of breaker bar on centre nut wheel turned very slow and a fare bit of pressure but did turn , I then jacked up the n/s and turned wheels they go in different direction o/s turned forward n/s goes backwards ' no side play on either wheel or no noises , i have no problem reversing on full lock either left or right no tramping or skipping. I will get mrs to drive it tommoro and i will sit in the back and see if i can locate the sound its bit hard to when driving to isolate the sound better thanks guys

Need to add a weight to your breaker bar. Most use 1.2m bar and 5kg.

Looking for a time around 30 seconds to drop 45 degrees, there is a Hippo video on you tube showing you how.

Thanks just done that my breaker bar is just over 3ft so extended it to just under 1.2m added 5 kg to it wheel turned nice and smooth took approximately 4 5 seconds to lower about the 45 degrees give or take but no hesitation at all .
But i have looked at the VCU and it looks a lot newer than the rest of the prop assembly no surface rust . As having no history i wonder if the VCU was replaced but the damage may have already been done cheers

OK. If the old vcu was left on then several things happen usually.

Front diff mount tears as the diff tries to go up at front due to wind up.
Diff gears get ground into each other and sometimes shatter.
IRD gears get ground up and sometimes case fractures under the extreme load.
Drain IRD and diff oil and report back !

andyfreelandy said:

OK. If the old vcu was left on then several things happen usually.

Front diff mount tears as the diff tries to go up at front due to wind up.
Diff gears get ground into each other and sometimes shatter.
IRD gears get ground up and sometimes case fractures under the extreme load.
Drain IRD and diff oil and report back !

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Think the IRD case fracturing is more due to worn DS drive shaft support bearing going.

Hi going to check oils over the weekend but the VCU does not look that old and seems ok with the OWU as checked yesterday will keep updated thanks

and11 said:

Hi going to check oils over the weekend but the VCU does not look that old and seems ok with the OWU as checked yesterday will keep updated thanks

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You really can't tell from looking at them. They can look basically brand new but be knackered. However, from your posts it does sound like its in decent nick. Best to do an actual comparison though with a 1.2m bar and 5kg or 8kg on the end of it.

Indicentally, its its a recon, they usually have the end of the 'drum' cut off so they can be cleaned out and then it is welded back on. So if there's evidence of welding, it may be a recon - but then I'm sure there's plenty of recons coming to the end of their life to

and11 said:

Hi going to check oils over the weekend but the VCU does not look that old and seems ok with the OWU as checked yesterday will keep updated thanks

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Does it have identical tyres all round, with the least worn on the rear?
Odd tyres can cause strange wear characteristics, and eventually damage the IRD and diff.

Hya tyres are identical passed mot today with flying colours but that does not mean much mrs traveled in the back and said the noise is more noticeable on the passenger side so i will check diff oil first what

and11 said:

Hya tyres are identical

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With the least worn on the rear?, this is important.

yes they are but the tread on one may be a bit less and thinking about it that tyre is on the n/s i will check the tread depth to be sure thanks

Hi guys all done had mot passed with flying colours.
Had 2 new tyres no noise from the diff front or rear it was one tyre that was causing all the problems out of shape.
Just got to sort the sun roof out opens but makes a ratchet noise when closes. Wit don't close without help but no problem as i am not likely to be using and looking for a dome light as map light do not work. But thank you all for help cheers

Nodge68 said:

With the least worn on the rear?, this is important.

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Got to ask a dumb question ..

If the VCU kicks in if the difference is ( say 5% ) between the speed of the front wheels and the speed of the rear then it wouldn't matter which was the largest....still be 5% difference ?

Or am I missing something in the way it works.....which is highly likely...

Kevm said:

If the VCU kicks in if the difference is ( say 5% ) between the speed of the front wheels and the speed of the rear then it wouldn't matter which was the largest....still be 5% difference ?

Or am I missing something in the way it works.....which is highly likely...

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The rear diff isn't the same gear ratio as the front, it's a fraction lower in ratio.
This gearing difference was designed to make the FL1 effectively FWD until the front wheels lost traction, at which point the VCU will drive the rear.
However the side effect is a drive reversal the rest of the time.
This basically means that the rear half of the propshaft is actually turning slightly faster than the front half, with new identical tyres all round.
Now if the rear tyres are more worn than those on the front, they will spin the rear half of the propshaft even faster than the front half, which causes the VCU to start transferring drive from back to front. This overloads both the IRD and rear diff in a direction that neither component is designed to take lots of torque, making one or both component fail quickly.

Kevm said:

Got to ask a dumb question ..

If the VCU kicks in if the difference is ( say 5% ) between the speed of the front wheels and the speed of the rear then it wouldn't matter which was the largest....still be 5% difference ?

Or am I missing something in the way it works.....which is highly likely...

Click to expand...

Its not the percentage difference that makes a VCU 'kick in' - its the speed difference.

At 60mph the VCU is spinning at over 3,000rpm. The differences IRD front/back axle gearing is much less than 5%, but small differences at 3,000rpm creates a lot of sheer. Going round a bend at 20mph, the VCU is still spinning at 1,000rpm.