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[Jan Suhr]

Might also be worth replacing the oil in the diff if it is a LSD.
Be sure to use a mineral oil with the GM LSD additive.

^^^ This ^^^

And you MUST use the additive. The additive is a friction modifier which allows the diff plates to slide smoothly over each other. If you don't use the additive the plates release and grab suddenly, which isn't good for any of the LSD gubbins. It causes the plates to get very hot and wear rapidly, and ultimately this wrecks the LSD.

Yes I know about the additive and its importance. Been a GM-guy for over 40 years and on the US Muscle cars that additive were very important too.

There is no problem to get it here in Sweden too since we have a lot of old American muscle cars over here.

Some of the rear end oils already have the additive mixed in the bottle.


Thanks

[Jan Suhr]

I had recently the rear end lowered when I put in new springs and shocks. The rubbers that I saw wasn't damaged.

[Jan Suhr]

Ok I have now changed the oil in the diff.

The old oil didn't look bad or smelled more that they usually do.

I still get the vibration when turning but I think it is a little better than before. I have driven it around the blocks for a few kilometers to get the oil working.

At least I now know that I have oil in it 


If it doesn't get any better I guess I have to find a replacement.

[0795omega]

could allways just live with it mine does this allso!

[polilara]

could allways just live with it mine does this allso!

Yes, as mine, but do you have it like Jan Suhr informed: "there is no vibration when the car just roll around a corner. It only vibrates under power"??

I cannot test it now as I am changing springs, shocks, wishbones etc, but I will do it when ready.

[LC0112G]

My understanding is that once the LSD plates are damaged they are basically scrap, and there isn't much you can do to fix them except replace.

The LSD plates can warp or become pitted. Warping happens when the oil gets too hot. Pitting is caused by micro welding where the heat of the slipping diff causes the plates to instantaneously weld together and then break free again. This roughens the surface and causes more heat/micro welding/pitting. Ultimatley it's down to the oil breaking down or no/insufficient friction modifier.

Replacing the oil can help quieten things down again for a while, but it can't fix any warping or pitting.

It's also possible that one of the bearings inside the diff is damaged, but you'd expect that to show up when driving/accelerating/overrunning straight and level too.

[Jan Suhr]

My understanding is that once the LSD plates are damaged they are basically scrap, and there isn't much you can do to fix them except replace.

The LSD plates can warp or become pitted. Warping happens when the oil gets too hot. Pitting is caused by micro welding where the heat of the slipping diff causes the plates to instantaneously weld together and then break free again. This roughens the surface and causes more heat/micro welding/pitting. Ultimatley it's down to the oil breaking down or no/insufficient friction modifier.

Replacing the oil can help quieten things down again for a while, but it can't fix any warping or pitting.

It's also possible that one of the bearings inside the diff is damaged, but you'd expect that to show up when driving/accelerating/overrunning straight and level too.

Well that explains it in my case and what I suspected. The former owner was a young guy who did some burnouts with it. A lot of rubber in the rear wheel houses.

The car is in very good shape besides this, a few minor things still to fix. I will start to look for another diff.

Thanks

[Jan Suhr]

A question regarding this.

Is there a difference in gears between manual or automatic transmissions.

I see that for 2.5 or 2.6 litre cars there are three different gears, 3.70, 3.80 or 4.22

I have found a couple of them on Swedish scrap yards but they are all from manual cars.
The lists also show that the 2.2 litre has the same gears.

Edit: I found on https://www.opel-infos.de/modelle/omega_b2.html that the 2.2 and 2.6 with automatic trans has the same gearing at 4.22. There are a few of them available here.



Thanks

[LC0112G]

If you open up the diff you'll find it's basically 3 parts -

1) the input drive pinion (leave this alone)
2) the crown wheel
3) the "centre"

The crown wheel bolts to the centre, whilst the centre contains all the LSD gubbins. So....

If you get a good LSD from a scrappy but the gear ratio is wrong, then you can just open up your existing diff, whip out the centre+crown wheel, swap the crown wheel onto the centre from the good diff, and re-assemble. This means you're using your old pinion and crown wheel (so the gear ratio is the same) but a new LSD centre.

Obviously there is a bit more to it than that, and you must ensure the backlash and side bearing preloads are correct on re-assembly.

Disclaimer - I've not done an Omega diff but I am in the middle of doing a Lotus Carlton one (which uses cones not plates) so the internals are similar. Hopefully it'll be going on the car this weekend.

https://www.aussiev8.com.au/driveline-suspension/71923-btr-m78-diff-question.html

[Kevin Wood]

https://www.aussiev8.com.au/driveline-suspension/71923-btr-m78-diff-question.html

Someone's been busy.

[Doctor Gollum]

A question regarding this.

Is there a difference in gears between manual or automatic transmissions.

I see that for 2.5 or 2.6 litre cars there are three different gears, 3.70, 3.80 or 4.22

I have found a couple of them on Swedish scrap yards but they are all from manual cars.
The lists also show that the 2.2 litre has the same gears.

Edit: I found on https://www.opel-infos.de/modelle/omega_b2.html that the 2.2 and 2.6 with automatic trans has the same gearing at 4.22. There are a few of them available here.



Thanks

3.2 auto should have a 3.9 diff

[Jan Suhr]

A question regarding this.

Is there a difference in gears between manual or automatic transmissions.

I see that for 2.5 or 2.6 litre cars there are three different gears, 3.70, 3.80 or 4.22

I have found a couple of them on Swedish scrap yards but they are all from manual cars.
The lists also show that the 2.2 litre has the same gears.

Edit: I found on https://www.opel-infos.de/modelle/omega_b2.html that the 2.2 and 2.6 with automatic trans has the same gearing at 4.22. There are a few of them available here.



Thanks

3.2 auto should have a 3.9 diff

Yes I saw that I had edited the wrong value after I had edit and it wasn't possible to edit again :-(