500SL rear axle whining

[RayHeath]

New to forum, just registered today.

I have a 1992 500 SL and two weeks ago (when ambient temperature was -7 degC) it developed a whining noise from the rear. I suspect differential. Main dealer replaced seals at 48000 miles. I purchased car at 53000 miles. It now has 61000 miles and only 22 months since main dealer resealed the differential.

What I have done to date:

1) checked fluid level, it was fine
2) changed tyres as I had recently replaced these and wanted to rule out tyre noise. It wasn't tyre noise

I have looked at various sites and the recommendations seem to be

1) change the fluid
2) check engine and differential mounts
3) check wheel bearings
4) live with it

The fluid has only been in there for 13000 miles and people who recommend changing the fluid say do it every 36000 miles.

The whining noise starts at 2mph (creep) and increases with speed. At 50 mph it takes on a louder tone. It is more noticeable during overun when there is no engine combustion noise. Putting the automatic into neutral makes no difference to the whining noise.

What should my plan of action be? Over to you guys.

Thanking you in anticipation.

Ray

 

[piestore]

diff whine

Hi Ray

doesn't sound good, when the dealer resealed the diff do you know if the pinion seal was replaced, if so it sounds like they have not set the preload on the pinion bearings incorrectly, but this should have been apparent from day one.

The other possibilitie is that the pinion nut has come loose this is quite easy to fix but take great care not to over tighten it.

 

[TonyCoolDaddy]

Is the noise definitly central, could it be road wheel Bearing?

 

[RayHeath]

Great question. I think it was coming from the offside rear.

As we speak, the garage has taken the rear bearing out but guess what? They haven't got a replacement so I have a car with three wheels now!

 

[Placey]

Ray - I have a 500 SE 1992 [not sure if the diff is the same or not]. It began to whine and over about 1000 miles, it became really bad. The diff was removed and the two bearings were found to be shot. With new seals/bearings / fluid I am looking at a bill for about £400 [specialist diff / gearbox garage near Preston] - not too bad considering. If the worm gears had been damaged, it may have been nearer £1000 or so, but these are pretty tough.

Hope info helps.

 

[RayHeath]

Thanks for all your advice. It was a pinion bearing. The diff was rebuilt at Ace Gearboxes Northampton. Refined motoring has returned.