Resetting Clutch Plate LSD (Cusco)

lovey80 · Post by **lovey80** » Mon Aug 27, 2012 12:36 am

So as stated in another thread I was having a problem with my R160 Cusco LSD. The issue occurred when turning under low load. If powering in a turn, the diff would lock and I would get some tire scrub, but under parking type conditions or even turning at a set of lights, to call the vibration/clunk,/cracking in the rear as anything other than violent would be understating the issue. The car simply wasn't drivable without the belief that serious damage was being done.

Having never removed a diff in my life I was a little daunted, however the lack of funds had me having to step up to the plate. Having Rick(RTCB) on speed dial was a great help in the process of removing the diff.

BTW the diff is a female type R160 that has had the brumby ends swapped to take the male splines that go into the diff.

I'll go through what I did just in case there is another member that is in the same situation and never done it before. Sorry for the poor pics on my Iphone. A big thank you to Rick and the beauty of the internet for my research.

So the first photo shows the only signs of damage I saw throughout the whole process. I'd like some comments on this if you guys have seen this before as I am have no idea how these marks could occur.

The second photo shows the cam. As you can see the dome shaped cam is sitting inside a triangle. This indicates that I have a 1 way diff, not a 1.5/2way which is fine for me as I am not racing it. A 1.5 way will have a kite shaped diamond and a two way will have a proper shaped diamond.

So first step is to remove the crown wheel as seen in picture three. Simple enough by removing the 8 bolts.

Once that is removed we need to open the diff centre up. There is four hex screws under the crown wheel that are quite tight so make sure you have the allen key seated before cracking it. A crap photo in picture four.

lovey80 · Post by **lovey80** » Mon Aug 27, 2012 1:09 am

Once the four screws are out the diff centre will come apart in two pieces. Make sure that the flat part of diff (planetary?) is uppermost or the LSD may fall apart on you. Once off, hold your hand over the guts and flip upside down so the centre is in your hand. Place it down on one side so the plates don't come apart. Then gently put it on it's side so the springs don't come apart. I made this mistake and it was very fiddly to get it all back together.

The first picture shows the springs and the clutch plates. You will notice that the clutch plates have seating flanges on them. They are spaced one with the flanges on the outside and one with the flanges on the inside. In this particular diff there is 8 in total each side. Larger diffs have at least 10. You can only see the external flanges in the photo.

From what I can understand from my research and the groves on the clutch plates, only an external flange plate will grip against an internal one. So in the original setting this diff is set up for maximum "locking" ability.

I chose to reduce this by swapping half the plates around in a hope that it would fix my issue. You can see in the second photo that I have chosen to put two external together then two internal together then the remaining 4 as standard. So effectively, I have reduced to about 7 friction points from the original 9. So reducing it's slip reducing ability by a little over 20%.

It all went back together in reverse. The hardest part with the diff centre was getting the centre back together because once pressure is taken off the plates the springs want to come out of their slots and the plates simply wont go back into the centre for it to be able to be screwed back up. I eventually, got it in there and spun the diff and used a small screw driver to move the springs into line (through the holes in the casing) so it would come together.

Getting the stub axles to ram home back into the diff was a complete prick but I eventually got it.

Once all back together it seems to have fixed the problem 99%. Only the occasional clunk out of the rear and no when near as heavy. Down the track when the diff begins to wear I will pull it all out and put it back to standard.

Hope this helps someone out in the future.

lovey80 · Post by **lovey80** » Mon Aug 27, 2012 1:11 am

I can only assume the changing of the plates was the solution. Maybe there was another issue with it that I managed to correct when it went back together (spring putting uneven pressure on the plates maybe?). Would love to hear the experts comments.

YouTube · Post by **El_Freddo** » Mon Aug 27, 2012 10:55 pm

LSDs that are wound up tight will create a fair clicking/cracking sound and send a shudder through the car. I'm sure this is what you were experiencing!

As for the marks on the diff's housing, it looks like the pinion gear has been fouling slightly, but I'm sure you would have heard/felt this earlier on.

Cheers

Bennie

lovey80 · Post by **lovey80** » Wed Aug 29, 2012 6:27 pm

Yeh mate there was so much noise, and clunking going on I didn't know what was going on. Im not sure what you mean by wound up tight though. Other than reducing the amount of friction points there is no way of resetting the pressure being applied.

What do you think would cause the pinion gear to foul the housing?

YouTube · Post by **El_Freddo** » Wed Aug 29, 2012 6:41 pm

No springs in there? I'm sure what you've done is the way to do it but I don't know as I've never done anything like that before - actually I've not had the chance to play with a LSD.

I don't know if it is actually fouling, if it was I'm sure you'd hear about it or it's got some wear marks in it. But what could cause it is an incorrectly setup diff from what I understand about backlash etc - Again I'm limited on this, it's something I need to learn!

Cheers

Bennie

lovey80 · Post by **lovey80** » Thu Aug 30, 2012 12:43 am

Check out the first image in post 2. The springs would be new so I guess they will get weaker in time. I'm still getting some unpleasant noises and clunks out of the rear but no where near as bad

lovey80 · Post by **lovey80** » Fri Aug 31, 2012 12:22 am

Ok after a trip to Brisbane and back I am 99% certain that part of my diff problem has come back. It seems that the pinion is fouling on the diff housing when I turn a corner. If anyone could give some advise on this it would be greatly appreciated.

Smokey · Post by **Smokey** » Fri Sep 14, 2012 12:10 pm

Just caught up with this thread now. Mate if your still having these issues. Can you swap in an open diff for now? That will buy you some time and prove beyond all doubt that it is in fact the diff. As you said it looks good inside and just may not be the diff at all?

For the cost of a spare open diff it might be worth a shot. There must be plenty of people around your area that can sell/lend you one.