Oil leak from rear diff breather

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Kungfu0210

New Member
Posts
124
Location
Warwickshire
Hi all,

Bit of a weird one this and i'm trying to get my head round what has happened, so any suggestions would be great.......

I got back from a 45min drive, mainly motorway and then 5mins of housing estate. As I pulled onto the drive I could smell diff oil (my mrs thought it was very sad that I knew the oil by smell !)

It was night so the next morning I took a look underneath and noticed that the back of the car had oil residue where it had been vented out of the rear diff breather tube. To the extent that there is even some light spray up the rear door.

Now..... I'd got badly worn front tyres last week to an illegal level on the inside edge (they had lasted 64,000 miles though so not all bad). ATS didn't have Synchrones any more only Latitude so I went for those as they are 30% discount if you buy 4. But they only had two in stock so I had them fitted to the front on Saturday and then they ordered the two for the back to come later this week.

So it ocurred to me yesterday that maybe the diff issue was that they were diiferent sizes, and sure enough despite the fact that both Synchrone and Latitudes are 225 55 r17, the actual measurement from floor to top of tyre is 4cm different between them !

Thus i'm running the back axle with tyres that are 4cm diameter smaller than the front, which i'm guessing has upset my rear diff, caused it to overheat and blow the excess pressure and oil out of the breather.

Please can anyone tell me if that sounds feasible as a root cause ? The rear axle will be going faster than the front so i'd think that I may also have upset my VCU ? Luckily the other two Lats are now in stock and i'm having them fitted today. Tippex test of the VCU next methinx !

Ta, Rick.
 
Good move on the tyre change. Your higher rear axle speed will cause locking of the VCU and hence back drive the IRD. Transmission wind up here we come. The rear diff and the IRD will both take a hammering. Get your tyres sorted and try again. Worth checking your diff oil level obviously.
 
This should never have been an issue, name and shame the tyre depot........muppets. It would have not been an issue if the tyre were a least the same profile.

Do they know anything at all about tyres?
 
4cm is a huge difference - in old money that is about one and three quarter inches !!!!

Can't be right ?


Certainly would bugger the drivetrain.
 
My first sticky - yey ! That means I must have done somthing really stupid ! ;)

Tyres were exactly the same profile 225 55 r17, and even the same make Michelin but the reality of the measuring tape showed a difference of 4cm diameter approx. It didn't help that they left the new pair pumped up at 39psi whereas my old rears were running 29psi.

New rears now fitted as well, and so far all seems ok. Plan for tomorrow is the tippex test just out of interest.....

Thx for the replies, Rick.

PS... You're right Willo, it does say in the owners manual to fit new tyres to the back, just read it now.
 
To be honest i personally don't believe in the best tires to rear bit. . . .the front ones always wear first,and provided you've got all the same type [and make] it don't make any difference if yer front ones are worn a little bit then swap em to rear [evens out] the problem is if they are badly worn. . . . . .just my opinion , and yes i do myself without any problems :) :) :)
 
To be honest i personally don't believe in the best tires to rear bit. . . .the front ones always wear first,and provided you've got all the same type [and make] it don't make any difference if yer front ones are worn a little bit then swap em to rear [evens out] the problem is if they are badly worn. . . . . .just my opinion , and yes i do myself without any problems :) :) :)

Is this real or is it just a mirage ?????:D:D:D






(The fact the post came from ming that is .......:p)
 
MING!!! Where have you been?? The tractors are everywhere, get your blaster gun at the ready. :D

Seriously, good to see you around again.

I heard the tratter boys took him hostage and made him do norty fings AGAIN!!!!:eek::eek::eek:

I also heard he escaped by covering himself in KY jelly and squeezing himself through the bars of the blue oyster club

:D:D:D

:welcome2:back Ming:)
 
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I heard the tratter boys took him hostage and made him do norty fings AGAIN!!!!:eek::eek::eek:

I also heard he escaped by covering himself in KY jelly and squeezing himself through the bars of the blue oyster club

:D:D:D

:welcome2:back Ming:)

Is the expression "poor sod" appropriate here ?? (I just ask this in view of my language barrier).:welcome2:
 
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