Hello,

I've got a 94 disco 88k that I got used a couple months ago. As part of routine service, I drained the diffs. The rear was gray and dark but after adding new oil it flushed clean. After draining the front, I flushed with another 4 quarts and still got nothing but thick gray oil. Does this mean it was just dirty or is dirt somehow leaking in through a seal to make it so bad. Since I can't clean it out I'm going to drive a week with the new oil and drain it. Then just do that every week until its clean. Is there an "ATF flush" type of method for really dirty diffs?

Thanks,

RM

 

You have a bad water leak causing that grey build up.
I would check and make sure you vent tube is not broken .
Change the fluid drive it for week or so and change it again, keep doing that till all that old junk is gone.

 

The gray oil is grease from the CV-joint seal its the sealbetween the
axle and the round ball next to the wheel.

At first the CV-joint housing was filled with gear oil and it would
leak, so it was changed to a gray grease to stop seal leaks at the
ball pivot.

When you change the brake disks you get a seal when you get
a brakekit.