Rear diff casing leak

[bungle]

Hi I'm after some advice on possible causes and solutions for a leak in my rear diff. I've had a good search of the forum but have only found threads relating to the drive shaft seals.
There has been a slight leak from the rear diff since I've owned the car coming originally from the o/s drive shaft seal, I recently had both these seals changed and this leak has now moved to the casing right at the bottom of the difference where two parts bolt together. The oil that is leaking is a healthy looking red colour so I'm not concerned about the oil, just wondering why the leak has shifted.
I am thinking it could possibly be a pressure issue with the AYC system forcing the fluid out at the weakest point. Other than that I'm stumped. As for solutions I was thinking possibly a new pressure switch for the AYC pump or separating the difference and applying some sort of jointing compound to reseal the diff. You can see some sort of sealant between the casing which is a red colour. I will post a pic of the diff when I get home later but I was wondering if anyone else has any thoughts on what it could be so I can get this fixed and avoid cooking my diff. Thanks

[Nick Mann]

Are you sure that it isn't dribbling down from higher up? The orangey red sealant is standard from factory.

[bungle]

I've just had a look under the car the only other place it looks like it could be coming from is the little casing nut just above. The one located underneath the 2 pipes that run from the AYC pump. Can't upload a picture for some reason

[Davezj]

There is a breather hole on top of the diff for both sides of the diff, if you over fill the diff with oil it will get blowed out of the vert hole.

[Adam.Findlay]

Are you sure that it isn't dribbling down from higher up? The orangey red sealant is standard from factory.

Factory sealant is threebond which is grey. Orange/red sealant means the diff has been apart although AFAIK the only place sealant is used on an AYC diff is on the inspection plate and pinion flange, as the rest is all O-ringed

[Nick Mann]

I have seen a lot of orange sealant. Is it different on the gearbox? I can't believe I have seen so much orange sealant that it isn't factory spec, but it could be that the orange is only on the gearbox....

[TAR]

My diff bad a hairline crack just above where the AYC bleed nipples are. It took me a while to realise that the AYC fluid was leaking from there. I think someone must have over tightened the nipples in the past. I've now fitted a new rear diff.:happy:

[Nick Mann]

Factory sealant is threebond which is grey. Orange/red sealant means the diff has been apart although AFAIK the only place sealant is used on an AYC diff is on the inspection plate and pinion flange, as the rest is all O-ringed

Just had a look at some pics, searched on rear diff and looked at threads with attachments that looked likely. I found three examples of orange sealant on rear diffs. Surely they can't all have been rebuilt?

http://www.clubvr4.com/forum/showthread.php?44954-Rear-diff-for-lunch-anyone-*munch*-*munch*&p=494352&viewfull=1#post494352
http://www.clubvr4.com/forum/showthread.php?71903-Questions-with-replacing-rear-diff&p=784833&viewfull=1#post784833
http://www.clubvr4.com/forum/showthread.php?3851-Txfer-box-Diff-amp-AYC-Oil-change&p=32568&viewfull=1#post32568

[hbkuk1]

I'm with nick my gearbox and diff had orange sealant before rebuilt. Now it's grey

[Davezj]

My PFL gear box and diff had orange sealant, mitsi must have changed the type of sealant used or the manufacturer must have changed the colour at some point in the build of the parts
Maybe mitsi just thought like the rest of us the orange sealant did not look very professional.
Also if the sealant is not very visible it stops people like me from picking it off.
Which can cause issues. Like leaks on the gearbox end plate. Never pick at sealant , if you want to remove the excess for any reason then use a shape blade to trim it flush never pull it.