Classic Technical Question regarding Rear Diff

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hef19898

Well-Known Member
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Dear LandyZoners,

I made a discovery today, not sure if I should be troubled by it so. After I removed the rear propshaft last week I spent some time under the car today. It turned out that the flange for the prop shaft on the rear diff has play, I can turn it by hand something between 5° and 10°. Also the diff housing is rusty as hell, especially the drain plug. I didn't check the oil yet, but it is on my list now.
So, is that can of play normal or a sign for something worse? It was also this propshaft that had min. one shot ujoint and showed vibrations when decelarating at around 2,500 to 3,000 rpm.

Greetings!
 
No up down movement! I'll call that good news then! We'll see how things go when the propshaft is back in.

Thanks for the super quick answer by the way!
 
Just another thing to add on the list... My wife is REALLY going to kill me. Maybe I can sneak it under hear nose at it is not visible without crawling under the car?
 
Up to now I didn't want to change the diff oil right now, but I guess I change it along with the gearbox and engine oil while I'm at it.
 
Up to now I didn't want to change the diff oil right now, but I guess I change it along with the gearbox and engine oil while I'm at it.

Your post reminds me of a query that I had intended throwing open to debate :
The manual recommends renewing the diff oil at 12 (or is it 24k) so why would my front diff oil often be dirty enough to require changing at service intervals of 12/18 months when my RRC has only done around 2k in that time? Over the same period the rear diff & transfer box oil remains clean o_O
For the cynics among us I've been advised of this by my erstwhile 'indie' & now he's retired my local garage, both of whom I have every faith in & used for years.

nb: if it makes any difference, the car does not off-road.
 
Your post reminds me of a query that I had intended throwing open to debate :
The manual recommends renewing the diff oil at 12 (or is it 24k) so why would my front diff oil often be dirty enough to require changing at service intervals of 12/18 months when my RRC has only done around 2k in that time? Over the same period the rear diff & transfer box oil remains clean o_O
For the cynics among us I've been advised of this by my erstwhile 'indie' & now he's retired my local garage, both of whom I have every faith in & used for years.

nb: if it makes any difference, the car does not off-road.
Maybe the front diff works harder because of the steering. Having said that, the front diff oil stays clean on my P38 so maybe your diff is eating itself:eek:
 
Oil does have an "expiry date" after which the performance levels that they offered can no longer be guaranteed/Maintained.
 
Your post reminds me of a query that I had intended throwing open to debate :
The manual recommends renewing the diff oil at 12 (or is it 24k) so why would my front diff oil often be dirty enough to require changing at service intervals of 12/18 months when my RRC has only done around 2k in that time? Over the same period the rear diff & transfer box oil remains clean o_O
For the cynics among us I've been advised of this by my erstwhile 'indie' & now he's retired my local garage, both of whom I have every faith in & used for years.

nb: if it makes any difference, the car does not off-road.

What is happening to the oil/grease level in the swivels?
As far as I know there is a seal keeping the swivel separate to the axle, if this seal is shot then "one shot" swivel grease (for ex) can find it's way into the axle, this is dark in colour so it could make the axle oil look dirty.
 
What is happening to the oil/grease level in the swivels?
As far as I know there is a seal keeping the swivel separate to the axle, if this seal is shot then "one shot" swivel grease (for ex) can find it's way into the axle, this is dark in colour so it could make the axle oil look dirty.

Right, so I will ask the garage if they observed an excessively high oil level in the diff prior to deciding to renew it. The swivels are lubed by 'one-shot', if the seal(s) are leaking oil into the axle/diff would the same apply in reverse? Perhaps I should ask for the swivel levels to be checked.
 
Maybe the front diff works harder because of the steering. Having said that, the front diff oil stays clean on my P38 so maybe your diff is eating itself:eek:

That's a worrying scenario though there's no indication of excessive wear, total lack of any noise or vibration etc & the cars' only done 58k from new with a FSH.
 
Right, so I will ask the garage if they observed an excessively high oil level in the diff prior to deciding to renew it. The swivels are lubed by 'one-shot', if the seal(s) are leaking oil into the axle/diff would the same apply in reverse? Perhaps I should ask for the swivel levels to be checked.
you cant check swivel level if they have one shot in them, just see some is in there, its common for the swivel grease to contaminate front diff turning oil black, it wont hurt though
 
you cant check swivel level if they have one shot in them, just see some is in there, its common for the swivel grease to contaminate front diff turning oil black, it wont hurt though

Thanks for that reassurance James. Probably a silly question but is it just a case of poking something into the housing & seeing if there's lube on it when withdrawn or reverting to EP 90? The swivels were drained & one-shot substituted back in '08 though a small amount was added during a service by my (then) indie in late '16. Due to the cars' low annual mileage that was only 4k ago.
 
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