How do I stop a droning rear diff?

[alanbp]

Hi

This is my first posting on the Merc forum.

Last August I bought a 1993 190 1.8 Manual with 108k miles.

The car is in generally good order with a few niggly issues, one of which is the constant drone form the rear diff especially around 50 mph. It occures on acceleration, coasting and on the overrun.

I drained the old oil and judging from the corrosion on the top-up and drain plugs it hasn't been touched for a good while. (I had to use heat to get the drain plug out)

I refilled using a polythene tube & funnel from above the rear wheel cos access is such a pain!! and even jacked up the front of the car as well as the back to keep it level and get all the Hypoid oil in. I used slightly thicker EP 90 rather than the 80 as specified.

I still have a droning whine. It actually seems worse but its probably as I get used to the car. I have read that its a common fault on higher milage Mercs and that it usually doesn't get worse and isn't hugely serious, but is there anything I can do to remove the irritation (other than turn up the CD player!!)

The car is so smooth & refined otherwise (apart from the agricultural manual gear change (& I thought Citroen's were bad!!)

Cheers in advance

Alan

 

[Parrot of Doom]

Get it re-conned?

 

[duncane]

Hi Alan,

Sounds familiar! I also bought a manual 1.8 190E with 108k miles on it back in August. I have had a number of problems with it, one of which was a noisy rear diff. I got a scrap one from mercman for £250 quid which has been good. I have read on a number of posts on this forum that using Molyslip can help in reducing the noise of a rear diff.

I also had the front coupling replaced as it was badly worn (£35 for the part, plus 1.5 hours labour).

plus had to get a new cat which set me back £275.

After all that I had to get the radiator replaced last week! Bugger!

Now though it is a nice car to drive, although as you say the manual gearbox did can take a bit of getting used to.

 

[tom7035]

Alan, I sympathise. Something like this spoils the enjoyment doesn't it! If it's as bad as you may consider another unit, then before you take the plunge how about first trying an ounce or so of flaked graphite in the oil, if you can still get the stuff (was used for lubricating locks). Many, many moons ago I had great success with this in an old pre-war Rover 14. So far as I know, the same diff. died with the rest of the car eventually!
Yes, I can just hear the sharp intakes of breath from you all - but if the diff.'s knackered anyway, no harm in giving it a go, it's a great deal better than sawdust, which ruins the seals!
You would be wasting your money with 'Molyslip' if the drone is as bad as you say.
HOWEVER - having said all that, you say the drone is constant, which is a bit unusual for a diff. noise - have you considered worn wheel bearings?

 

[television]

108K is nothing for a MB diff. The pinion bearing is the piece that goes normally but you only ever hear this on the over run and not when the car is pulling. I think like Tom says could be a wheel bearing.

Malcolm

 

[mike4444244]

hi
i agree, if you have changed oil it is unlikely to be diff, my dads has done 300K miles and is fine, check for play in wheel bearings and propshaft couplings, might just be that you need a new prop!
mike

ps if you think that gearchange is bad you have obviously never driven a landy!

 

[Ian Brown]

Mercedes 190 1.8 are notorious for diff problems changing the oil wont make any difference to a noisy diff it is normally the pinion bearings that give the problem, better get the diff reconditioned by a good independent as the back lash on the diff has to be set up correctly or the bearings wont last if it is set to tight, or a lot of backlash if it is not tight enough it is crucial to have this set correctly. Take the car to a good gearbox repairer and have him listen to the noise, he should be able to tell you what it is that is causing the noise. The other option is to get a good second hand diff.

 

[tamrsoft]

I agree with Tom7035 and TV, my wifes bimmer 3 series has suddenly developed a severe whine from the rear which is there all the time the car is moving and not just when under power. Since worn diffs do not usually whine on overrun, wheel bearings are a distinct possibility.

 

[QUOMAN]

if not a wheel bearing and you do suspect the diff call 020 8853 3343 or check this site www.greenwichcarparts.biz

 

[nautic]

had my 190e diff rebuilt at 130,000 miles. cost me £500. the bearings were badly pitted.

 

[190e-nut]

if the Gearchange is so bad maybe it's the box ? just a thought...I have owned 6 190's and it's only been the cars with Manual Gearshift that have made a whining noise ....the Auto's have always been silent ...

 

[Ian Brown]

if the Gearchange is so bad maybe it's the box ? just a thought...I have owned 6 190's and it's only been the cars with Manual Gearshift that have made a whining noise ....the Auto's have always been silent ...

Have they been 1.8 or 2.0 litre because the 1.8 is bad for noisy rear ends?

 

[190e-nut]

2.0 litre ...my current car is a 1.8 ..and it's whisper quiet

 

[Guy Greenwell]

Noisy Diff

I too do not think this is a diff. problem. Differentials are usually only noisy when under load and occasionally on the overrun.
Try listening carefully when going round a bend, the noise will probably increase or lessen in severity. the faulty bearing will be on the opposite side to the direction you are turning to, unless lie me you are unlucky enough to have both sides fail together (It was on my Range Rover & due to water ingress when wading).
Also try jacking the wheel up and turning by hand. The faulty bearing can often be felt as being slightly rough and have free play if the wheel is grasped and rocked top to bottom, handbrake off, wheels chocked.