Rear Diff Problem - Im a noob please help!

Hi Guys,

Just Got myself a 300tdi Discovery, L Reg, 212k (yea i know its high but it was cheap and has a good service history)... However I have just noticed that there is oil running down the rear diff seems to be coming from above/on top of the diff, any ideas what this could be/how to fix it? Ive been taking it greenlaning alot lately but have been fairly careful, although i did hit a pothole fairly fast the other day, maybe this has caused it :S any help is much appreciated!

Many Thanks
Paul

fer fooks sake get underneath an have a look we can't see it from here.

Disco rear axles are prone to the diff pan rotting at the top as the fuel tank shrouds it from view so it never has the crud cleaned off it (I know because mine was like that), that is more than likely where your leak is.

Just to clarify what was just written, the diff casing rusts clean through and the oil comes out the hole even if the hole is near the top, because the oil is flung up by the crownwheel.

If it's a just a wee hole a temporary fix can sometimes be done with a SHORT self-tapping screw and a fibre washer under its head.

Temporary fixes sometimes last for many years ....

I'll have a look tommorow, but i did have a quick look today and the case did seem quite rusty, hopefully the hole is only small but if not i guess i'll have to replace it, anyone got any ideas how much id be looking at to get it replaced?

Cheers, Paul

It can be a pain in the butt fixing these.

It depends on where the hole is. If it is HIGH up you stand a better chance of a quick fix with a self-tapping screw. If the first one won't grip, try a short fatter one! As they say, "If it's short and thick, it does the trick!"

You can get steel pans to weld over the whole rear end of the axle banjo, but this is quite a job to do.

Try a self-tapper and a fibre washer first, or even a self-tapper wrapped in PTFE plumber's tape.

There is no pressure involved. Just oil splashing off the crownwheel.

There are some other threads kicking about dealing with fixing rusted diff covers. The favourite fix seems to be sticking a blob of something called "chemical metal" over the hole.

When mine went on the bottom, I drained the diff, blasted all the rusty crap off - luckily there was some metal left after that - then stuck about 5mm of bridging compound over the entire area where the holes and thinned metal was, smoothed it off and painted the whole thing with red oxide followed by hammerite. It's been at least a year and it's been fine since, not a drop has reappeared and no more rust has appeared either.

try Easynetdial
its cheap and delivery is pretty good

Hi again! Just to let you know i seem to have fixed the leak now, i used the bonding compound and then a couple coats of hammerite, worked a treat! Was going to try a screw but i found the hole was about the size of a pin hole and wanted to cover it all to be sure it wouldnt leak anywhere else. Just wanted to say thanks for your help!

Paul