Diff oil leak

[Guest]

My diff has decided to get rid of it's oil, liberally covering the underside of the car and dropping a fair volume into the drip tray. I was prepared to change out the seals and gasket but they look intact, the amount of oil on the casing suggests it's come from somewhere else - is there a vent, core plug that's known to go?
The other thing is the colour of the oil, see attached, it looks like 2 different oils have been used. As I'm never keen on mixing oils I'll get the driff drained and refilled with a single type.
WP_20140624_003.jpg

Another thought is do I get a reconditioned diff? I'm paying a garage to do the work and the £440 Rimmers are charging for a recon unit will be pretty close to the labour charge to strip out the shafts to get at and replace the seals by my accounting. Labour rate is £40 an hour which is not expensive in this part of the world.

[stagwingnut]

Hi , well there is a type of pressure relief valve in the form of a pin on the top of the diff which can get blocked , u just have to locate it and pull it up and down to free it up !! But that won't explain the leak , it's obviously either a seal or a gasket , possibly a cracked diff through bad jacking !! The two different oil colours some one may have possibly used a diff quitening oil !! The pin is at the top of the diff on the off side of it ! re a recon diff many owners have found that recon diffs can still be noisy ! If yours is quite then it may be best to recon your own ! This is the dilemma of a recon diff , a bit of a gamble I'm afraid !! Regard Graham

[2V8s]

Thanks Graham,
I don't have a photo of the underside but there is oil liberally sprayed from the end of the prop shaft back across the fuel tank so I'm thinking that it's being ejected under pressure as it's able to go forward against the airflow.
Another piece of my thinking is that the garage is highly competent but this is their first Stag, so a diff swap may be a lower risk.
My diff isn't silent by any means but it's not bad, but you could be right on the quieting oil.

Paul

[wilf]

Sounds like the seal at the end of the extension housing is leaking, that is a common issue.

While it is out, you should think about fitting a strengthened extension housing. And the best quality bearing in it you can get (LD parts are worth talking to).

This isn't a job I personally would entrust to a garage that has never worked on a Stag diff before, sorry. If neither you nor they know exactly what is needed, I just don't see how it can end well. JMHO.

[2V8s]

In addition to the side seals and backplate gasket I've provided the diff front seal (Rimmers Part 137346) as this is the only seal I can find between the front pinion bearing and the extension drive flange. The bearing in the extension housing is noted in the manual as a sealed unit located by circlips. Is there a seal not shown on the drawings?

[Staggering About]

Paul, it would be worth talking to the local Stag expert Danny Taylor. he's been working on them since they were new. He also charges a lot less than your quote. I'll email you his details.
Alan

[jakesmig]

You're probably only leaking oil out of the quill shaft seal which is the one right behind the prop shaft flange. If your oil level is correct it usually half sits in oil, and the rotation of the crown wheel washes the oil in that direction as well. You may have wear in the quillshaft bearing which can cause leaking in the seal. The drive shaft seals are difficult to replace because you need a hydraulic press to get the flange off, so try the quill shaft seal first before you look at them.
If your diff isn't whining why replace it?

John.

[Mike Stevens]

There is no seal in the extension housing - it's in the nose of the diff itself and runs on the quill shaft where it connects to the 'coupling muff' (oo-er). The bearing at the other end of the quill shaft (just behind the prop flange) is a sealed for life type as it has no lubrication from anywhere else.

The front seal is easy (ish) to fit, but not so for the output shaft ones. The flange has to come off and that's on a shallow taper and sticks like you know what. A press in excess of 25 Tons will be needed and they let go with a big bang!

If the diff is quietish I'd replace the bearing and seal at the front - this doesn't disturb any of the diff settings - and make sure the jiggle pin is free. (Back, top on RHS). But there again I'd be doing it myself so not paying labour rates.

I suspect the oil colour is just due to deposits in there over many years of use.

Cheers,
Mike.

[73stagman]

I suspect the oil colour is just due to deposits in there over many years of use.

Cheers,
Mike.

My thoughts as well.
Could even be the results of old oil and condensation mix. (Because of the jiggle pin breather thingy) As there is no drain plug in the diff as standard, unless the diff has been off and emptied out it may have very old oil and sludge in the casing..

[2V8s]

Thanks all.
This post has found me a Stag specialist not a million miles from home and the car is being repaired hopefully in time for the weekend. The preblem is a blocked vent leading to front seal failure, fortunately I've got the necessary parts so it's now a case of getting the diff out, putting in a new front seal and getting mobile again.

[Mike Stevens]

The preblem is a blocked vent leading to front seal failure

Very, very, very common failure on Stags, big saloons etc. I have to admit to having 'quite a few' like that in the last 40 years of Triumph driving.

Glad you've got it sorted, or about to anyway.

Cheers,
Mike.