KAAZ LSD - Clunky Clunky?? Solutions?

[nastylilweed]

Hey Everyone,

The KAAZ 1.5 way in the back of my Sprinter has got what I think is death clunk. Fortunately I have never had issues with diffs before, unfortunately this means I'm trying to work out if there is an in the mean time solution before going and getting a new center...

Explanation of Problem

The diff clunks on acceleration and deceleration both in straight lines and while turning, this is more noticeable at low speeds.

IE

In second gear, 40km/h and in a straight line the sequence would go like this...

Accelerate, clunk, punch throttle, clunk. It would appear to me that as long as positive pressure is applied through the diff there is no noticeable noise, it only occurs as positive pressure is released and reapplied.

It's a considerable clunk not just a panzy clink, it still lock up very crisp as I would expect it to. IE I don't think it's a worn clutchpack issue.

SO I have come to the following conclusions,

- It's Spider Gear backlash (New center)
- It's Pinion / Crown Wheel backlash (Readjust / rebuild)

My question is, will running a different oil potentially help reduce this issue? My main concern is that it has a TRD Crownwheel and Pinion in it (IE expensive) and don't want to destroy them in the case that I need a new center.

Any help would be super rad!

Cheers,

Joe

[CRONIK]

Easiest way to check pinion to crownwheel backlash would be to grab the tailshaft and twist it back and forth to feel how much play there is. It should have a bit of play between contact but not much.

Other possibilty could be axle tramp? you havent lowered the car recently or set the diff on a funny angle so the pinion isn't facing straight to the gearbox/tailshaft?

[nastylilweed]

Thanks man, ill check the tails haft movement. On the note of play when I had the rear up in the air the other day playing with suspension I was looking at the play in the axle. The wheels free spin about 10-15mm when turned... It seemed a bit excessive which is another reason I thought it may be spider gears...

And no, not recently lowered or played with. It appears to be sitting in line with the gearbox output...

Thanks for the reply,

[maxhag]

Hey Joe,

I bought a Brand new KAAZ 2 way, had it professionally setup in the housing, did the wear in as it said on the KAAZ instructions, and used the KAAZ oil supplied with it.

It did the exact same thing as you have described. And I do mean exact.... It did it for 2 years (then sold the rear end. (R31) ), but the diff performed very well the whole time. It was a very good LSD centre as far as performance..
Oil changes never had metallic particles......

Some of the clunks sound pretty nasty hey, and I always thought something was gonna break, but it never did.

Thats all I can really say to help you.......

JoJo

[nastylilweed]

Hmm that's pretty suspect hey. I have heard many stories of people saying that after market centres are noisy and concerned about the horrible noises they made. It's weird that it would happen from new after everything was set up correctly...

I have read a couple of posts etc suggesting that a different oil has reduced the noise. Which tbh I'm not concerned about noise, I'm concerned about what the noise means and the shenanigans it may be causing, and in that light less noise equals less nasties.

Is it possible that it's clutch pack movement in the cage that's creating the clunk? It seems like a legitimate answer but I'm not sure if it's practical...

I'll do an oil change this weekend and see what difference it makes and if there are any nasties...

Recommendations and experiences with clutch lsd oils? I've head red line works well in these?

[maxhag]

I just always used the KAAZ oil when I had that KAAZ centre. Used to buy it off Ebay......

[nastylilweed]

Thanks man, I don't even know whats in it at the moment and it's probably due for a change anyways... I'll get onto it this weekend and report back if there are any nasties.

Anyone else got any knowledge they feel like sharing?

[maxhag]

A few years ago I did find a video on you tube. It was in America, KAAZ in a 180sx, and it was clunking the same as ours..... The guy was asking for help, but there wern't any replies....

[johl]

from the symptoms i would say your lsd is fine. its locking up so i would say your problem is backlash. i had these exact same noises coming from my old car whenever i was came on/off the throttle. it is a 2 minute fix to adjust the backlash but thats once the centre has been removed. i just took the entire assembly still in the nose cone and a mate fixed it up for me.

as mentioned above turn the tail shaft and see if there is excessive movement, or if you have a decent shop near you it would take a few seconds to put it on a hoist and have a mechanic feel the tail shaft and he will tell you if its too loose

[Prime86]

Hey Joe

I know of a few cars that are fitted with the Kazz 2way centres and from new they do the exact same thing. I know the guy who owned the car before you and was asked by him about it also as it did it from the day it was fitted. When he fitted the new diff he put rose jointed rear trailing arms in the car also which made it 10 times worse so he removed the arms thinking it was them making the noise. I'm actually surprised its still in there as he told me he was going to change it for a TRD centre or Cusco as they don't clunk or bang as they lockup and unlock.
If your worried about it I would suggest removing it as you can just pull the diff hat out with the gears etc to check it properly. It's easy to do takes about 2 hours if your working slow and you don't need any parts to do so. That way you can check the wear in the diff gears, axle bearings and the centre itself along with checking backlash for piece of mind. I would steer away from the old just give the tail shaft a clunk back an forth as there could be another problem down the line with uni's etc, check the parts individually to isolate the problem. I have all the specs if you need any just give me a txt.