Diff oil leak

[cliff.b]

Checking under my car and noticed evidence of an oil leak from the front of the diff (see pic).

I also noticed that the exhaust passed directly under the diff and is very close, maybe about 5mm.

Just wondering if this is likely to make the diff excessively hot and if so, could that be thinning the oil and causing the leak?

[Steve P]

Not unusual for the front seal to leak,worth checking the jiggle pin on the top as it acts as a breather,no breather = pressure and more likely to leak.

Don`t think the exhaust makes too much difference,use a good quality oil- EP90 GL4.

Some on here have looked at modern synthetics but i have no experience of those.Changing the seal isn`t a massive job.

Steve

[Pete Lewis]

the exhaust has no effect the diff gets hot enough to fry eggs in normal use as waste energy is given off as heat 

and if you take the coupling off to change the front seal(after checking the breather its just above the filler on the NS )

turn the prop shaft bolts around   you want a good clearance on the front frame  4 bolts as if one comes loose you lock up the prop

Pete

[cliff.b]

Hmm, decided I better top the oil up if it's been leaking and a steady drip started coming out when I removed the filler. I added a bit more anyway but the drip turned into a trickle then. I am therefore assuming that as it has clearly lost some oil, it was probably overfull to start with and maybe that's why it's been leaking.

 

[Clive]

11 hours ago, cliff.b said:

Hmm, decided I better top the oil up if it's been leaking and a steady drip started coming out when I removed the filler. I added a bit more anyway but the drip turned into a trickle then. I am therefore assuming that as it has clearly lost some oil, it was probably overfull to start with and maybe that's why it's been leaking.

 

Diffs are often overfilled as the cars get hacked up at the back so the car is at a jaunty angle.

However, seals do not seem to last forever, so keep an eye on it. I hope you have checked the breather. And honestly, get the level correct  and then see if it leaks. Otherwise you will not have any idea if there is an issue to fix.

 

[cliff.b]

47 minutes ago, clive said:

Diffs are often overfilled as the cars get hacked up at the back so the car is at a jaunty angle.

However, seals do not seem to last forever, so keep an eye on it. I hope you have checked the breather. And honestly, get the level correct  and then see if it leaks. Otherwise you will not have any idea if there is an issue to fix.

 

I looked for the breather (not for very long) but couldn't find it. What am I looking for?

Also, the oil that did come out was black. Is that usual? Don't think I have ever seen used diff oil before.

[Pete Lewis]

even if verfilled the seal must do its job  if  it leaks its shot it has to contain the splash oil from the rotating crown wheel 

which throws oil  at the pinion bearings  with far more force than any  overfill

sorry this is coupling off and dig the old seal out examine the coupling seal surface for a wear line  and fit a new seal 

Pete

edit 

the breather and filler are on the casting at the NS output  shaft zone  the split pin sits above the filler on top of the cast shape 

diff oils dont get contaminated as such  so black is either an addative ,or its been cooked  or its rubber from the seals 

best access is remove NS wheel and look thro ' the chassis 

Pete

[cliff.b]

Many thanks for all advice 👍

[Mjit]

1 hour ago, cliff.b said:

I looked for the breather (not for very long) but couldn't find it. What am I looking for?

Take a look at the image of the 3.89:1 ratio diff on the Rimmers site - https://rimmerbros.com/Item--i-RTC2305R

You can see the breather pin on top of/just ahead of the big hole for the rear mounting bolt on the D/S.

[GFL]

Wow! £636.00 for a recon Diff from Reemers!😬

Another thing to check when you remove the Drive flange is check if it's worn or rusty/pitted were it contacts the seal, this must be smooth with no marks or pitting or it will still leak with a new seal?

I fitted a double lip seal on my old Vitesse with a new drive flange, getting the old seal out is a bit of a faff, I used an old screwdriver to punch and lever the old seal out.

Good luck  

 

[cliff.b]

Again, many thanks all.