rear diff whining only underload, which part to replace?

Hi lads.... as title says im getting a whinging noise coming frm the rear of my v8 classic iv just brought, im presuming its the rear diff? The noise only comes when accelerating, rolling or cruising at same speed all is good.
Now when I first picked her up I didn't notice this noise, drove 180 mile bk frm north Yorkshire without any problems at all, brilliant drive in fact, I first noticed the noise the following day, my guess is the rear diff was either low on oil or jst worn out gruddy oil and iv fried my diff as I was doing a steady 80 all way bk, oh I mean 70 even with our ****ty motorway network! Lol
so my question is what part do you lot think needs replacing? Obviously a bearing or two I should imagine but iv nevet touched a diff so not sure where, how easy to change ect or is it just best to source a reconditioned one?
Or could it be a rear wheel bearing? As the noise is slightly to my left.
Also im puzzled as to why it only whines when accelerating?

thanks for any advice lads, ladetts!!!

Check the wheel bearings before you look at diff. If you don't know what you are doing don't play with the diff.

wammers said:

Check the wheel bearings before you look at diff. If you don't know what you are doing don't play with the diff.

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Hi mate... when I say iv never worked on a diff doesn't mean im not capable of it, im a mechanical engineer by trade so im prity sure its not beyond on skills.
I just thought it best to get some advice from ppl who's done it befor is all.. altho I could do it blind im not one of these guys whos to proud to ask for others advice, tips ect..
so yer befor I stripped the dif down I thought id ask if the symptoms are simaler to other ppls diff problems ect ect...

but alas I shall just crack on with it and see if I can spot the problem, if not a new diff it is!!
or hopefully just new wheel bearing!! Lol but I doubt it is the wheel bearing, changed plent of them and its never happend when accelerating only, iv found when a wheel bearing goes its more a constant groan be it accelerating or cruising, but I shal soon find out..

all best...c

discocheese said:

Hi mate... when I say iv never worked on a diff doesn't mean im not capable of it, im a mechanical engineer by trade so im prity sure its not beyond on skills.
I just thought it best to get some advice from ppl who's done it befor is all.. altho I could do it blind im not one of these guys whos to proud to ask for others advice, tips ect..
so yer befor I stripped the dif down I thought id ask if the symptoms are simaler to other ppls diff problems ect ect...

but alas I shall just crack on with it and see if I can spot the problem, if not a new diff it is!!
or hopefully just new wheel bearing!! Lol but I doubt it is the wheel bearing, changed plent of them and its never happend when accelerating only, iv found when a wheel bearing goes its more a constant groan be it accelerating or cruising, but I shal soon find out..

all best...c

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If it only makes a noise under load then something worn is being thrusted against to make the noise. Just a matter of finding it. Diffs are not hard to do, but there is a bit of know how required. Likely diff, but you said it was coming from left side. So checking wheel bearings first is the easier option. Although as you say wheel bearings are usually constant. Could be left side carrier bearing i suppose. But everything is a guess until you get into it and find the true reason.

There's a very useful guide to replacing/repairing diff here:- http://www.landyzone.co.uk/lz/f38/how-replace-diff-input-bearing-64301.html

I suspect I'm going to be doing mine - a rumble (like an exhaust rumble) from the rear on neutral throttle/overrun at 60mph ish. A non-constant rolling noise from what sounds like wheel bearings from the outer (loaded) rear wheel on curves, (but only on neutral throttle). No oil leaks though.

I first need to check the oil level, but the fill plug is rusted solid, pen oil soaking and wire brushing in progress . . .

Good luck.

A

odyssey said:

There's a very useful guide to replacing/repairing diff here:- http://www.landyzone.co.uk/lz/f38/how-replace-diff-input-bearing-64301.html

I suspect I'm going to be doing mine - a rumble (like an exhaust rumble) from the rear on neutral throttle/overrun at 60mph ish. A non-constant rolling noise from what sounds like wheel bearings from the outer (loaded) rear wheel on curves, (but only on neutral throttle). No oil leaks though.

I first need to check the oil level, but the fill plug is rusted solid, pen oil soaking and wire brushing in progress . . .

Good luck.

A

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But that is NOT the correct way to rebuild a differential.

wammers said:

But that is NOT the correct way to rebuild a differential.

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Could you elaborate please Wammers?

odyssey said:

Could you elaborate please Wammers?

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Not without filling a full page. The way described will do a job, but not a proper job. Setting a diff up properly is not quite as simple as that. Not quite the same as the Land rover diff set up but this will give you the idea. http://www.youtube.com/watch?v=dAqAqODmcj4

Thanks for that Wammers - very interesting, I'll cogitate for a while and see what the oil in my diff is like (assuming I can ever get the plugs out, and there is any oil in it) and take it from there . . .

Alastair

mateys a little over kill for an already used lr diff ie has been set up correct previously , setting is straight forward if you use timken bearings and diff carrier preload is very simple which incorporates backlash at the same time

jamesmartin said:

mateys a little over kill for an already used lr diff ie has been set up correct previously , setting is straight forward if you use timken bearings and diff carrier preload is very simple which incorporates backlash at the same time

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Yeah i know James but just giving an idea to those who may think diff rebuilds are straight forwards sometimes depending on what you find they are not. And yes backlash and carrier pre load are very easy on the Land rover diff.

wammers said:

Yeah i know James but just giving an idea to those who may think diff rebuilds are straight forwards sometimes depending on what you find they are not. And yes backlash is very easy on the Land rover diff.

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it is if your rebuilding a previous set one and havent removed crown wheel but are just swapping bearings as since it ran well for years you can take it was set correct

jamesmartin said:

it is if your rebuilding a previous set one and havent removed crown wheel but are just swapping bearings as since it ran well for years you can take it was set correct

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If crown wheel and pinion are in good condition and you are changing all the bearings. After changing pinion bearings all you need to do to set crown wheel is tighten one side until there is no backlash, then tighten other side until you get .007" job done. But the biggest wear items are the planet wheels and pins so as i said before unless you do everything it is only half a job.