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cubehopper

Ongoing rear end problems

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After sharing my ongoing problems with a whining noise from the rear end I thought I`d post an update.                                                                                          After rebuilding the diff with new bearings, but the original c/w and pinion, and getting a good contact pattern,  the noise  from the rear end still persisted, even after altering the backlash and  the contact pattern numerous times, the noise was still there, exactly the same , a droning starting about 40mph and continuing with increased speed.The noise was there when accelerating/decelerating,coasting in neutral, and when clutch pressed. After removing/reinstalling the diff at least 4times I had had enough and decided to cut my losses and exchange it for a recon diff from Moss with a new   c/wheel and pinion. Great, I thought, problems solved, a rebuilt diff with all new parts from a well known respected company who must have sold hundreds of rebuilt diffs.  Not quite, after  installing the Moss diff the problems are still there, nothings changed at all, same noise under the same conditions.   I cannot believe that I have exchanged a faulty diff for another faulty diff and a load of cash  so  that means the problem must be somewhere else, but  where ,the hubs  were exchanged a few years ago but haven't done more than 6000 miles and the  bearings rotate smoothly , all the u/joints are well greased with no play, the propshaft and gearbox feel fine.  I`ve been in touch with Moss  who tell me its rare for a rebuilt diff to be noisy  and suggest putting the car on  a 2 post lift and running through the gears   whilst listening to the diff, and if it proves to be faulty they will replace it . So this is where I am at the moment £ 600 down and nothing achieved. I am struggling to retain my enthusiasm for my car after 20 years of ownership  and don't really know what to do next, apart from torching the b***dy thing.

I would welcome any suggestions/advice /opinions, as I am sure many members must have been in the same boat.

cheers, a desperate Dave

 

                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              

                                                                                                                                                                                 

 

                                

 

 

 

 

 

 

 

 

 

                                                                                                                                                                                                              

                                                                                                                                                                                                                                                                                                                                                                                                                               

                                                                                                                                    

 

               

 

 

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I hear your pain and frustration. There's two things you can do, either leave it till something breaks and then you'll know for sure or get a second opinion. 

It sounds like a great idea putting it on the lift and then listening to all the moving parts to help track it down, I think you can hire some time at a few places around the country to do that. 

Good luck with your next move, but while you're in the mood to torch it, leave the problem for a while and regroup. 

Gareth

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It could be the treads on a tire, I had that problem with my '73 911.

I replaced the rear wheel bearings and the noise persisted- turns out it was a weird worn Michelin.

Try moving the rear tire (s) to the front.

Cheers, Walt

 

 

Edited by Sapphire72

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Gareth/Sapphire72

After one of the changes I made to the diff settings I ran the car through the gears on support blocks and didn't hear any noise from the diff/rear it was only when the weight of the car was on the ground on a test run that the noise started again.                                                          I`m not that sure whether running the car on supports is a substantive way to find a drive problem as the load on the wheels and moving parts are not really being replicated in the same way as when the car is on the ground  moving under its own steam.

I did think about a potential tyre problem so that might be a good idea to move them about.                                                                                        The tyres are about 7 years old and the contact area spends winter months not moving position so it might be a flat spot or internal problem.

cheers a more positive and less sulky Dave

 

 

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I hadn't followed your original problems, but what sort of diff mounts are you using, are they poly ones or some nice soft rubber ones, I have heard it makes a big difference to noise,  could also the pins front and back be correct dimensions, if not quite in the right distance apart could that be loading the pins/mounts when tightened up?

Strange with so many different diffs already fitted you still have the noise.

John

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Sorry to hear this.

I would make an appointment with Moss, so they can drive the car and here the noise themselves.

Waldi

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Hi John,                                                                                                                                                                                                                                                 I have only had two diffs, my original one I rebuilt and the Moss exchange one.                                                                                                              The mountings are standard rubber and the pins are original.

rgds Dave

 

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1 hour ago, Sapphire72 said:

It could be the treads on a tire, I had that problem with my '73 911.

I replaced the rear wheel bearings and the noise persisted- turns out it was a weird worn Michelin.

Try moving the rear tire (s) to the front.

 

 

I had that same experience on a golf !

maybe swap wheels with another tr and test?

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Blocks or Lift does not do anything since you are not inducing the load on the wheels, shafts etc. 

Rolling road would be better. 

I do not believe it is the diff especially after replacing it. Is there any play in the diff rocking the wheels back and forth? Ideally, there should be some of it. No play at all, may be too tight. 

As suggested above, swap wheels and look into your drive shafts. 

Jochem

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Hi Dave

I'd put some money on it been a tyre.

Had a very similar issue recently with a BMW X3 front tyre which sounded very much like a front wheel bearing, there above 20mph, in neutral and coasting esp on very smooth roads all the drive train checked out fine. The tracking was out by only a couple of degrees enough to feather the outside edge of the tread blocks so it was "flapping" the ground. Tracking adjusted sound gone.

The rear trailing arms might be out of alignment have you hit a pot hole or kerb or is there significant corrosion to allow the mountings to move or bush failure? Check there alignment/adjustment but as said I'd start by changing the tryre's around cheaper than another diff.

Keep us posted.

Andy 

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Dave , are you sure it's the diff? ..... my 4A started making a horrible droning noise some time ago and it turned out to be the output bearings in the A type overdrive, I changed them and the noise was gone, .... BTW I had a rebuilt diff with new CW&P from Moss around 5 years ago, it has been perfect.

Cheers Rob

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Have a look at the very rear of the diff where the front of the spare wheel well comes down, I had one here that sounded like it had a running washing machine in the boot going up the road, the rear of the diff mounting was just touching the spare wheel well. I have also had similar noises when the exhaust just touches where it goes through the "T" shirt.

Stuart.

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Thanks for your suggestions guys they have given me a few things to check over the next few days.

Rob - happy to hear that your  diff has been ok, thats   reassured me that mine should be ok.

One other thing I need to check is the rear mounts.I changed them when doing the first rebuild attempt of the diff and wonder if this has had any bearing on the problem.  They are the standard rubber ones, which I have always used before without any noise problems, and when tightened ,the inner sleeve, which protrudes a couple of mil above the rubber, clamps between the chassis and the lower large washer .This has always bothered me, as the large washer hits the step on the pin before the sleeve is really tightly clamped,   I would have thought that when the nut is tightened, the large washer should  compress the rubber mount tight against the chassis to absorb any movement , but  there is a gap of 1-2 mm. between the chassis and the rubber. Although I`ve never had any noise problems  with this arrangement before so I`m probably clutching at straws but I`ll look at anything.

cheers   Dave

                                                                                                                                                                                                                                                                                                                                                                                                                        

                   

 

 

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Hi Dave, sorry to hear about your rear end drone issues.... As you may have seen in another recent thread I've just resolved a previously grumbly TR6 diff with a rebuild. As you've swapped your diff completely it does suggest it's something else.

As others have said, do try and swap the tyres/wheels about. My father had a Zafira which had an awful speed related drone at the back. Really intrusive, well we replaced both rear wheel bearings and it remained the same. Heads were scratched. A few months later he had a bad rear puncture, a rear tyre was replaced and noise gone completely!! I'd never believed a tyre could sound so bad, but that one obviously did....!!! 

Good luck, cheers, j.

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If all else fails, it may be time to see if you can find out anything more by loading up the diff on a rolling road and listening/looking around the back. 

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Thanks for your suggestions, changing the wheels front to back and vice/versa will be  my first  job ,hopefully later in the day.

Mike - This might be the way to go before I start tearing things apart, it should be possibly a way of isolating the noise to the offending item.

cheers   Dave

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