Differential Venting

[vande17941]

Is there any other reason that fluid would seep or drip from thevent other than the differential being overfilled and fluid expansion when hot? If the differential is slightly overfilled, will it just come out the vent until it is at the proper level?

I know about proper procedures (level axles etc) for filling.

Just wondering if the vent serves any other purpose.

[ja17]

 Not so much because of expansion. Overfilling, might cause the oil to foam-up and exit through the vent.

[gorgoo]

Hello,
To adjust diff level, you just have to remove the plug at the back of diff casing.
Vent is much higher than this, serves only to compensate for temperature (hence oil volume) changes. If you get oil throuh the vent, it means serious overfilling (how can you do that?) or as serious overheating. Either you're driving 180mph all day long or something is wearing quickly, worth an investigation anyway.
Didier.

[Tyler S]

The Diff level should be checked and filled with the axles level. If the veh is raised by the body, the axles will pivot down and the diff will be overfilled.

[Benz Dr.]

I have a hoist where the rear axles are not supported. As rule, I try to stick my little finger into the fill hole and as long as I can feel oil it's OK. I only add when I can't feel anything. Once the car is on the ground and moved a head about 10 -  20 feet, which is important to get the axles leveled out, then the oil level will be just about right. I'd say that the oil level should be about 30 - 40 mm below the fill hole with the axles not supported.

[Tyler S]

So now we need a measurement of Dan's finger added to the tech manual. 

[vande17941]

There's my diff problem....I have it filled, axles level, right up to the very edge of the fill hole.

[kampala]

Vande17941,

There's my diff problem....I have it filled, axles level, right up to the very edge of the fill hole.

You may want to re-read the last few messages --- you might be mis-interpreting. 

[Benz Dr.]

So now we need a measurement of Dan's finger added to the tech manual. 

 Not your standard finger length. I'm 6' 4'' so everything grew long on me.