HELP - Oil leak

[gsd2000]

To start off with i was driving over some speed bumps and heard a banging from the boot, at first i thought the boot was open as I'd taken my mum shopping. I had a look and i think it was just two cans of holts tyre weld bouncing about.

I decided to have a look underneath and noticed some oil stains on the exhaust and parts of the diff. Jacked the car up and found this













The stains of oil seem to be in a coming from the bolts on the front of the diff. I assume the bit between the diff and the prop is my doughnut.

Is this serious?

Can i complete the dyno day safely without breaking the diff?

What could be the cause of problem?

Seals gone in the diff?

I know some of the photos are not brilliant but it was the best i could do

[MyM8V8]

The oil,looks as if its coming through the splines as the nose of the diff is dry so its not the shaft seal.

If it's knocking like hell you need to see if the coupling has movement. Only thing I can think of is that the nut holding the coupler on has come loose. But normally they are bked up real tight.

As to the loss of oil, you would need to check the diff oil to see how much you have lost. You don't want to be running without any oil there.

[monkfish1]

WHS^^^^.

Looks like the oil is coming up the splines rather than past the seal, which suggests that the nut is loose which means you have lost the preload on the pinion bearings.

I wouldn't recommend running it like that. As it is, you might getaway with some loctite and retorquing it.

[gsd2000]

I assume the you are referring to the coupling as the part covered in oil?

There are no oil stains on the drive or anywhere where i have parked up.

I will take the car for a quick drive now and listened out for any knocking. The knocking was more of a banging but only when i went over a large speed bump a bit quick, never noticed it going around corners.

If its not knocking i will quickly check the oil tomorrow morning.

I assume to check the oil all i do is undo the top fill plug?

Should the diff be full up to the fill plug?

If its still leaking and lost a fair bit of oil i will have to pull out from tomorrow's dyno day

[gsd2000]

crap, just read monkfish's reply. Suppose i will have another good look tomorrow, add some loctite and retighten. I have warrenty, just hope they cover the diff, other wise its a second hand one or a 3.91

[monkfish1]

gsd2000 said:

crap, just read monkfish's reply. Suppose i will have another good look tomorrow, add some loctite and retighten. I have warrenty, just hope they cover the diff, other wise its a second hand one or a 3.91

You will need to have the prop off and the rubber coupling too. Then remove the pinion nut and degrease. the problem now is that the pinion preload is set using a collapsible spacer. Not enough torque and it will come loose. Overdo it and you will have bearing failure. Strictly speaking it cant be done, it should be stripped and a new collapsible spacer fitted.

I have done it, but by feeling how much preload and thus resistance to turning the pinion. Problem is, with it assembled you only have the backlash movement by which to judge it.

[gsd2000]

i may have to trailer the car to you then to rebuild i will dig up my warrenty papers and have a good read. I just hope they cover it otherwise it will have been a very expensive year for me

[essexhsv]

Yep, Thats the same leak i had on my Ro.

Its the diff'd rear oil seal but when you drive the air under the car blows the oil up to the underbody then it drips down and goes on the prop and both sides of the exhaust.

I had a new seal fitted on its own the it leaked agian after on about 2 months or so.

Then it went back to Vauxhall and they fitted yet another seal but also the diff input shaft where the seal runs on.

Its been fine since then and no more leaks.

Is the underbody seaked above the diff?

[gsd2000]

there were oil stains above the front of the diff on the under side of the car

[mym8v8]

gsd2000 said:

i may have to trailer the car to you then to rebuild i will dig up my warrenty papers and have a good read. I just hope they cover it otherwise it will have been a very expensive year for me

Mate your not coming tomorrow. Sorry, gutted for you. But Rogers right, looks as though you will need a new crush washer. Unless you have been very naughty, this should be a warranty job.

If it sounds like a bag of bolts, don't drive it, you'll total the diff.

[gsd2000]

diff sounds fine apart from when i go over large speed bumps, but with it leaking oil, i don't want to make it worse by sticking the car on a set of rollers. I also don't have any diff oil to top it up with.

[essexhsv]

gsd2000 said:

diff sounds fine apart from when i go over large speed bumps, but with it leaking oil, i don't want to make it worse by sticking the car on a set of rollers. I also don't have any diff oil to top it up with.

Mine was leaking for weeks and i wanted it to run dry so Vauxhall would have to replace the whole diff but i never lost to lot.
Once the oil was low the diff didnt work that well and it would spin only 1 rear wheel as it worked like a normal diff.

[007 VXR]

mym8v8 said:

If you want to bring her to me now I'll stick it on the lift and have a look? I have some diff oil. I'm 12 miles down the A6.

tell you what ...this is why i love this place........
at 9.40 on a friday night

[mym8v8]

GSD2000 has just left. He will be coming down tomorrow, or is that later today!

[omalley34male]

hi i was to change exhaust and my prop axle bearing was shot so i mounted a new 2 piece driveshaft from dorman
i had leakage om the right hand cv axle seal and front input shaft seal but the nut was not hard tight at all
i just marked it up, took it of and replaced the seal but was that wrong..
do i need to have it to a profesional shop to get the right play in the diff?

Kjell from Västerås

[MyM8V8]

omalley34male said:

hi i was to change exhaust and my prop axle bearing was shot so i mounted a new 2 piece driveshaft from dorman
i had leakage om the right hand cv axle seal and front input shaft seal but the nut was not hard tight at all
i just marked it up, took it of and replaced the seal but was that wrong..
do i need to have it to a profesional shop to get the right play in the diff?

Kjell from Västerås

Simple answer is how does it drive???

You will need to get the pinion pre-load correct and that may require a new crush washer. If the nut was loose (you said not tight at all) and you marked it, that will not help you get it right. You might have some movement left on the existing crush washer, but to measure and set the pre-load with the diff in the car would be difficult if not impossible. If it was me, I would take the diff out.

Having said that, if the cars drives OK and the diff is not noisy, do you want the work?

[omalley34male]

MyM8V8 said:

Simple answer is how does it drive???

You will need to get the pinion pre-load correct and that may require a new crush washer. If the nut was loose (you said not tight at all) and you marked it, that will not help you get it right. You might have some movement left on the existing crush washer, but to measure and set the pre-load with the diff in the car would be difficult if not impossible. If it was me, I would take the diff out.

Having said that, if the cars drives OK and the diff is not noisy, do you want the work?

hi i just left it as it was but i have some terrible wibrations down at 50-60km/h after that its better and the slap in the transmision, axels and diff on my car is terrible
how you are fine and stayed helthy

[MyM8V8]

omalley34male said:

hi i just left it as it was but i have some terrible wibrations down at 50-60km/h after that its better and the slap in the transmision, axels and diff on my car is terrible
how you are fine and stayed helthy

Yes, Im OK thanks, how is Elise? Send her my best wishes. The axle fit on the Monaros are a bit sloppy anyway, and the diffs can knock. \not sure what the vibration is. If you have checked the wheels are balanced a new fitted a new prop shaft is the shaft properly balanced? The slap in the transmission could be the back lash setting. This is adjusted by the side carriers and is measured with a dial guage against a crownwheel tooth. I normaly set mine at 4-6 thousanths of an inch.

[omalley34male]

Hi long time no see
hope you all are fine
today we had some cruising in town the powermeet was not an option this or last year because of corona but we still hanging on
i had my car running a litle od when i start it it make some noice lika something is scraping and knocking and it stopps after a few seconds and today it was coming again and especially arround 2000rpm throttle of
i drove home and saw that left tail pipe was a pile of fine grains almost like sand but silvery and felt a little fat in consistance i hope it is from the catalyst and not from pistons otherwise im fked

Elise are fine i guess she is asleap now i will tell her you said hello

i had a bad summer this year as my father went in to the woods looking for muchroms and berries 4 weaks ago and never came back ..
our life is upside down at this moment and no one knows anything about him the police, military, hmeguard, dogs, helicopter has search for him and ended up with nothing

say hello to the other guys and take care of yourself and familly my friend
(Kjell.
..

[mfp4073]

That is very sad news about your father. I will say a prayer for him and that he is found safe and well.

With regards to your car it does sound like one of the catalytic converters has failed.
If the car is down on power and the fact you have residue building up in one of the exhaust pipes suggests it's breaking up.
The lack of performance is probably because the cat is blocked and not allowing the exhaust gases to escape properly.
I very much doubt the piston has failed, if that had broken up it would have destroyed your engine pretty quickly.

John