Driveline, gearbox or diffs noise!! but which one.

Recently I brought a 96 Disco 300tdi. I have a whining type noise which seems to come from the back but can't be 100% sure....... When pulling away with a good throttle I seem to get a whining in first and second but seems to disappear third onwards. During the first week I thought it maybe the exhaust touching the body as I accelerated because that is what the noise sounds like. After poking around underneath it seams that the whole exhaust is new and fitted correctly. All the levels are correct (I have replaced all the fluids with new oils) there is no strange knocks, clangs or sounds on either full lock, front n/s swivel seal is seeping but only a little. If you pull away normally with a light throttle or on a downward slope the noise does not appear to be there. I love my new old toy and I am not frightened to have a go but am a little nervous about changing/repairing the wrong thing.. I have read lots of threads concerning similar whining but can't find one that fits my symptoms exactly. Any ideas would be a great help.

there is a world of difference between exhaust noise and gear whine ,new cheap exhaust can vibrate between the two layers of thin tin on silencer when excelerating,you could remove rear prop and try it in difflock,check prop ujs for play and when removed that no joints including slide are tight ,no end float in diff flange and doughnut isnt cracking

With g-box whine expect more noise when the transmission is thoroughly warm, and the oil thins out. (Take a good half hour or more to do this, not just coolant temp). Also try dipping clutch when stationary in neutral: change in noise= gearbox.

Hellfire, super fast response. But I am 45 and it's been a few years since race tuning my first and second mini's. So I am just getting used to getting dirty again, the joys of British motoring. Donuts, UJs, is getting to technical to fast. Don't get me wrong I am confident it's not the exhuast as it seems well fitted with a new rubbers. It is hard to describe a noise isn't it?, more of a deep whine but only really during load (heavy throttle or up hill). Not having a disco before and only owning it for a week I am just getting used to driving it. There are no other symptoms at all. I am sure it could be any one of a number of problems but I would need to be helped in simpler terms. Thanks for your quick response.

you didnt read it properly as its not outside condition of exhaust but how well two layers are fastened together ,remove rear prop and drive in difflock first inspect prop at same time

HI gtland, thanks for your reply. The noise is no louder or quieter warm or cold. I have tried dipping the clutch and freewheeling with my balding head out the window and all seems quiet. I thick it comes from the rear but not positive.

hi i think it might be the rubber donut it is the rubber between the rear prop and the rear diff i had the same symptoms the noise when going up hills and under throttle took me a while to find the problem but eventually saw what i thought was string riund the rear prop shaft and the rubber donut had disintegrated and bolts were hitting of each other causing the noise.

Thanks James, yes i misunderstood a little. I will try your suggestion, when you inspect prop exactly what am I looking for? with the prop removed and drive in difflock what will this prove or disprove? thanks for your help, mark

Hi Whytie, this sounds like a cheap and easy fix. i will get underneath and have look tomorrow and also check prop, joints. If the donut looks ok then I will try Jamesmartin suggestion. thanks agin

ujs arent stiff or slack (free play ) doughnut is good ,removing prop will eliminate rear

Ok cheers james, I understand now, takes me a while but I will get there in the end..with a little help. raining like mad at the moment, oh and very dark lol. Praying for a dry day so the Mrs can have yet another view of my legs poking out from under the motor. Cheers all, Will check back again tomorrow.

ok let me know how you get on it is easy hardest part is getting the bolts out through the donut if it is as badly deformed as mine was the holes wernt even round when i found out what is was think the donut cost about £20

Quick question; when changing fluids you did change oil in axles too? And what came out was (more or less) the correct quantity and type, with no metal fillings or muddy water? Not trying to teach my Grannie to suck eggs, but often overlooked.

When i changed the fluids, both drain bolts were clean with little or no filings. Oil was very dark or even black but there were no nasties lurking about. The front was very low and had little oil at all but putting the correct amount of new in did not change the tone of the noise though. This was the first thing I did when I had the car because the biggest minus was the fact that the service book had only been stamped up to 72000 and it has done 135000. So I gave it a full service.. Had a look at the donut quickly this morning as it is still raining and I haven't the luxury of a garage. It looks to be the right shape, however I have seen at least three splits in it. Would this cause a problem/noise??

If it`s damaged replace it, but dunno if that`s the source of your noise? Try putting each axle in turn on strong axle stands and turning the wheels by hand. Look/feel/listen for any roughness or excessive backlash. Compare the two axles, and if possible compare with a known good `un.
Make sure the vehicle is well chocked as the h-brake works on the transmission and don`t use old bricks as axle stands. (Not having a go at you, but that`s for others reading this thread with less experience & sense!)

understood, made that mistake on my first range rover, I was a lot younger and new it all then..lol, no harm done and lesson learned. I will order new donut and check axles out at the same time probably next weekend now, I will post my findings next week.

youll learn more removing one prop at a time

how have you got on found the problem yet?

I had a look yesterda, although the donut looks to be in shape, there is three small splits in different places. so I have one on order off flebay and probably next weekend while changing it I will follow jamesmartin advice and drop the prop off and try it before fitting new donut. I will post findings next weekend. cheers all.

Hi whytie2607, Many thanks for your advise, I looked at the rubber donut and I could see some small splits. I ordered one for £15.96 off flebay, it arrived Wednesday. I dropped the prop off after work and was going to take jamesmartin's advice while it was off but alas the diff locks have probably never been used as the lever would not select them, H and L were fine. (another post perhaps). Anyway with the prop off and a closer inspection of the donut revealed it had indeed split next to every bolt hole. On top of that the four prop bolts at the front end were very loose (dangerously loose in fact) as well. I refitted new donut and the offending noise has totally gone..thanks for your advice all, especially Whytie. Another symptom I have noticed the very first gear change I made.....Before when changing gear there was a spongyness to the initial lift of the clutch when pulling away. And now that too has disappeared, my Disco is very smooth. thanks all...