Curious leak on diff/prop area

[Parrot of Doom]

While doing the ATF the other day, I noticed a spread of oil around the diff.

the patch was the upper offside of the car, just to one side and slightly above the diff. It wasn't thick, or dripping. It looked like oil had sprayed out of a leak on the diff somewhere.

We checked all the seals, mounts, rubbers, etc, and couldn't see anything suspicious. There was a thin film of oil around the case of the diff, but I've seen this on other cars I've owned and its never been a problem.

Is there a method for checking the oil level in the diff, how is this done, and what oil is used to top it up?

 

[GrahamC230K]

http://mbclub.co.uk/forums/showthread.php?t=3663

Mine was checked, I was told the level was fine despite the appearance. Been to two specialists now, same opinion.

 

[andy_k]

I wouldn't panic, they nearly all do this. You only need to start replacing seals if they are actually dripping oil. The filler plug is also the level plug but you'll need to check the capacity. A usual guide for diffs is half an inch below the filler.

They are nearly always a bit awkward to get at and generally located on the upper half of the rear face of the diff - usually you will need a square drive to undo them

What fluid you use will also vary depending on whether or not you have a limited slip diff fitted

all in all I'd get someone to check it for you and if they say nothing is wrong take their word for it

Andy

 

[big x]

This months car mechanics magazine has a feature on how to service a W202 C-class (orange Fiat Tipo on cover) includes checking the diff.
These cars are so easy to service it's amazing more don't do DIY.

adam

 

[Will]

From memory the diff filler plug is a 14mm hex/allen head bolt. You will need a decent socket type allen key to undo it.

HTH

Will

 

[Parrot of Doom]

I think there was something on the nearside of the diff case, but I didn't check further as we were busy doing other things

Thanks for the pic Graham, thats quite similar to mine except that there is a light covering of oil on the offside of the diff case, and the bits of chassis surrounding it.

My TVR used to do exactly the same thing. Its just that I have a persistent 'thrumming' from the rear of the car at about 55-70mph that I still haven't tracked down, despite 2 new rear tyres.

 

[Will]

Worth checking the propshaft couplings?

Will