I decided to fix the small leak on my differential today as it was leaving some drops under the car. At closer inspection it appeared to be leaking from the cover, a closer inspection revealed a few cover bolts not as snug as should be.

So, got 2 liters of 80/90W gear oil, removed the cover, cleaned and applied RTV, re-installed and re-filled. Looked ok for a few minutes until... leaks again!

It is actually leaking right through the steel cover. Looks like the cover has rusted to the point that it has small pinholes and the oil is leaking through, now much more than before with the new oil. These holes must be awfully small since the inside of the cover showed nothing.

So.. Here's my question:

Can I JB-Weld or epoxy the outside of the cover? Anyone have experience with either? Will it resist the oil? If so, should I apply epoxy or JBWeld to inside as well? Obviously I will prep the surface properly for adhesion, just wondering if it will hold up to the oil. What is better? JB-Weld or some type of epoxy?

Also, anyone know what the sensor is for on the diff cover? Fluid level?


Your responses are much appreciated,

Andre Corriveau
Ottawa, Ontario
87 745Ti AW71, 420,000 kms