Leaking differential?

[Jowe]

While I was hoisting my 230 to fix the fuel pump, I noticed that the differential was very oil wet and also the front part of the petrol tank. The car has run about 2000 km since exchange of diff fluid (Castrol Axle Z Limited Slip 90). I have not yet checked the current fluid level in the diff. Any obvious diagnosis ?

[jameshoward]

If it's wet towards the tank, it could be that it was overfilled (did you have the axle tubes level when filling - if not, it WILL be very overfilled, ie if you left the rear wheels hanging down). It could be a blocked breather that has allowed pressure to build up in the diff only to release under pressure. It could also be something else. I'd check the level with the car jacked and supported properly (ie in a way that keeps the tubes level as if the car was parked up) before driving it again and report back on what you find. If it is overfilled, be prepared for a lot of oil to come out when you open the fill plug. If it's OK, you could leave the car parked up and see how much seeps out. Diff leaks aren't often big and you can certainly live with a small leak.

[Jowe]

Thank's James. Yes, the oil was filled with the wheels hanging down, so I will follow your advice to check the level with the axles properly supported. Then clean up and have an eye on it after a while of driving.

[jameshoward]

Jowe,

Given that the wheels where hanging down when the oil was filled, you may need to keep a close eye on the oil seals at the wheel-end of the axle tubes. If you were unlucky, and if the seals are perhaps a little old, it is possible that they may have been damaged by the pressure. It's boring, I know, and not what you want to hear, but it's worth looking out for.

Good luck!

JH

[Jowe]

Yes, I will check that. On the plus side, I remember that I carefully measured the amount of oil that I filled the diff with...

[Benz Dr.]

Pinion seal and the boot leaking are usual problems. On the more obscure side, leak at the flange where the two halves join and a cracked or broken housing due to someone letting the right axle drop without any support. Both of these repairs require axle removal.