Outer Limits 4x4 Board

I have a GQ Patrol which is fitted with the factory LSD in the rear and was wondering if anyone knows the easiest way to test it to make sure it is working properly

aazz wrote:I have a GQ Patrol which is fitted with the factory LSD in the rear and was wondering if anyone knows the easiest way to test it to make sure it is working properly

A good quick test is to get your truck with one tyre on the bitumen and the other on the loose stuff and sidestep the clutch. If the LSD is working there should be little or no wheelspin of the tyre on the loose stuff.

With mine, I can get the tyre on the bitumen to chirp.

Nice. There's could still be a bit of spin on the dirt couldn't there? Might be a bit hard to tell. Easiest way I can think of to get a sure conclusion would be to jack one side of the axle up on a jack which can fall over (like the scissor ones sideways), just high enough to lift one tyre off the ground. Hop in the car and drive it in 2wd. You should be able to drive off the jack.

Anyone whose done this, can you confirm whether you might need a bit of hand brake? I'm worried, depending on how unstable the jack is, that using the hand brake would work regardless of the working of the diff.

Then again, I still don't own anything other than an open diff :(

If you don't like the idea of using the jack, you could always drive the rear wheel into a hole, keep it in the air and try to drive out in 2wd.

Heathx4 wrote:Nice. There's could still be a bit of spin on the dirt couldn't there? Might be a bit hard to tell. Easiest way I can think of to get a sure conclusion would be to jack one side of the axle up on a jack which can fall over (like the scissor ones sideways), just high enough to lift one tyre off the ground. Hop in the car and drive it in 2wd. You should be able to drive off the jack.

Anyone whose done this, can you confirm whether you might need a bit of hand brake? I'm worried, depending on how unstable the jack is, that using the hand brake would work regardless of the working of the diff.

Then again, I still don't own anything other than an open diff :(

If you don't like the idea of using the jack, you could always drive the rear wheel into a hole, keep it in the air and try to drive out in 2wd.

you will still have probs workin it out this way, as even good LDS's wont drive it out,

I dunno if this helps but on painted or slick concrete eg underground car parks my rear LSD goes CHIRP CHIRP CHIRP when I'm turning hard. Open diffs don't do that, nor, I suppose, would a buggered LSD.

One thing I hear is that the Nissan LSDs are very durable.

Jason

altho the nissan lsd's r great
i'm not sure that they will still work like a locker

therefore if a wheel is in the air.......no load......they still spin
so therefore u wouldnt b driving anywhere

thats standard lsd configuration if i'm correct

Do you have a 4.2 (petrol or diesel) motor or a 2.8? There is a difference between the LSD in these two models, the 2.8 LSD requires more cross-axle torque to make it slip - almost 4 times as much, yet still uses the same H233B centre.

Handbrake won't be effective on the spinning wheel, as it is driveshaft/transfer case mounted.

just drive around in a circle at full lock on loose stuff...grass or dusty concrete.
the jack thing doesn't work as the spinning wheel needs a bit of traction to make the lsd work.

Area54 wrote:the 2.8 LSD requires more cross-axle torque to make it slip - almost 4 times as much, yet still uses the same H233B centre.

Do you know the specs? I've been in a quest to tweak my Xterra's H233B LSD and I'm curious just how tight they can be tuned. Factory spec on my Xterra is 138-180 ft-lbs (101-132 N-m). I've noticed that the older WD21 Pathfinder specs 260-289 ft-lbs (191-212 N-m) though it appears to be all but identical other than the spring disc/plate components of the clutch pack. The older one uses a splined disc/plate pair at the outer end, while the newer one uses two smooth discs. I'm going to swap the WD21-differing parts into my LSD and see if it makes the difference.
Some guys here have been stuffing additional plates in the clutch packs and all but turning it into a spool, and I was considering that until I realized there was that subtle difference in the older LSD which I will investigate first.

Area54 wrote:Handbrake won't be effective on the spinning wheel, as it is driveshaft/transfer case mounted.

Very good point. Oh well, jack is no good then. Sorry

Unless... you get a good mate to hold the wheel that is in the air, while you give it some

I have a 4.2 diesel. When I hold the steering on full lock and turn in circles what should I be looking for? I have tried the one wheel on gravel and the other on tar trick and got someone to watch the wheel on the gravel it spun very easily and just kept spinning, I don't think the LSD is working. I have only had the car about 6 months and am not sure about the previous owners maintenance on the diffs. The car has 235,000 kays on it, could the LSD just be worn out and if so what parts generally need replacing.

change the oil in the diff for with some specific LSD oil, if you are certain ur diff is LSD, this could get it all happeneing again (my gq had almost 300,000 with the LSD still going strong)

It should be quite easy to get a hoon squeel happening if you plant the foot in the middle of hooking a 90 degree corner in first gear on smooth tar, then maybe this only works if you got secondaries

My rear LSD seems to work OK at 350,000km, but now not anywhere near as good as the front one I just put in

You cant test them easily due to the way they ramp up.
Chock front wheels.
To see if its a LSD jack both wheels off ground, trans in neutral, h/brake off, Rotate one wheel by hand. Both wheels should turn same direction.
Lower one wheel and try to turn again. You will just be able to turn it. Will get easier as soon as it turns.

They are not a locker and always need one wheel on the ground or a light app of foot brake/

bazzle

XterraGuy wrote:

Area54 wrote:the 2.8 LSD requires more cross-axle torque to make it slip - almost 4 times as much, yet still uses the same H233B centre.

Do you know the specs? I've been in a quest to tweak my Xterra's H233B LSD and I'm curious just how tight they can be tuned. Factory spec on my Xterra is 138-180 ft-lbs (101-132 N-m). I've noticed that the older WD21 Pathfinder specs 260-289 ft-lbs (191-212 N-m) though it appears to be all but identical other than the spring disc/plate components of the clutch pack. The older one uses a splined disc/plate pair at the outer end, while the newer one uses two smooth discs. I'm going to swap the WD21-differing parts into my LSD and see if it makes the difference.
Some guys here have been stuffing additional plates in the clutch packs and all but turning it into a spool, and I was considering that until I realized there was that subtle difference in the older LSD which I will investigate first.

The 2.8 LSD requires between 294Nm to 392Nm to get the diff to slip, as opposed to 70Nm to 137Nm for the 4.2.

LOL at Rainbow warrior, hoon squeel . All that TD42 power...

Area54 wrote:

XterraGuy wrote:
The 2.8 LSD requires between 294Nm to 392Nm to get the diff to slip, as opposed to 70Nm to 137Nm for the 4.2.

LOL at Rainbow warrior, hoon squeel . All that TD42 power...

TB42 actually, don't get a secondaries option on a TD42 AFAIK

Holy cow! The 2.8 has an insanely tight LSD!!! How in the world can that thing ever slip? Seems like it would just drag the inner wheel through every turn no matter what. No disrespect, but are you 100% sure about those numbers?

Agog...
Brent

Yep, straight out of the manual.

Rainbow, I was referring to the TD42 in aazz's rig.

Ive been wondering the same thing in my MQ, not sure how to test the LSD properly. So wats the go? Im not really in the mood to take it out and look so i spose there must be away?
I was thinking the Jack would work just dont jack it all the way clear on the one side, jack it only enough to be just scraping the ground and see if u can drive off?

unfortunatly with the old diesel motor i have way too much truoble trying to spin em with one wheel on the bitumen so thats out to.
wat u guys think?

Screwy

1. Place a jack under the diff centre (or two jacks under the diff housing if you have off centre pumpkin) and jack up both wheels. Gearbox in neutral and handbrake off, spin one wheel, both wheels should rotate in the same direction to determine you have an LSD. Lower rig back to ground.

2. Place jack under one side of diff housing, jack up until tyre is just off the ground, leaving opposite wheel in contact with the ground. Gearbox in neutral and handbrake off, rotate the suspended tyre (in any direction) and take notice of the initial force needed to make the suspended wheel spin and turn the driveshaft. You can measure this VERY roughly, with a torque wrench and socket on a wheel nut, and rotate the wheel, this is quite inaccurate, as you have bearing and seal drag in the diff, pinion and gearbox, as well as bearing preloads, but might still give you an idea or a measurement to go by.

There decent enough ideas. Might give them a hit this arvo.

Screwy

XterraGuy wrote:Holy cow! The 2.8 has an insanely tight LSD!!! How in the world can that thing ever slip? Seems like it would just drag the inner wheel through every turn no matter what.

Well aren't I the fool, I did the conversion backwards and got some insane numbers in ft-lbs. Re-doing my math, I see that it's not so wild after all. Not to mention I botched the ft-lb to N-m conversion when expressing our diff specs in N-m. My Xterra specs 187-245 N-m (figures given in N-m, kg-m, and ft-lb in my service manual). The WD21 would therefore have 352-392 N-m, which isn't so different than the 294-382 N-m of the 2.8L Patrol after all.

Brent

I have just got around to jacking up my car and it is an LSD. I then jacked up just one side of the car and spun the wheel. There was some resistance but the first revolution or when I first spun the wheel wasn't any harder than any other spin. I have changed the oil in the diff twice in about 500 kays, just to make sure, with Castrol LSX90 diff oil. I have also tried spinning the wheels on grass, gravel, tar and mixtures of both and the wheels always spin easily (except on tar TD42 power). I am assuming my LSD is stuffed. Oh well another weekend in the shed for Aazz & Dad Mechanical.

aazz wrote:I have just got around to jacking up my car and it is an LSD. I then jacked up just one side of the car and spun the wheel. There was some resistance but the first revolution or when I first spun the wheel wasn't any harder than any other spin. I have changed the oil in the diff twice in about 500 kays, just to make sure, with Castrol LSX90 diff oil. I have also tried spinning the wheels on grass, gravel, tar and mixtures of both and the wheels always spin easily (except on tar TD42 power). I am assuming my LSD is stuffed. Oh well another weekend in the shed for Aazz & Dad Mechanical.

Consider swapping it with an air locker perhaps, by the time you get your LSD rebuilt, you could go the extra to a ARB for $1000 plus a cheapo compressor to run it.

aazz wrote:I have just got around to jacking up my car and it is an LSD. I then jacked up just one side of the car and spun the wheel. There was some resistance but the first revolution or when I first spun the wheel wasn't any harder than any other spin. I have changed the oil in the diff twice in about 500 kays, just to make sure, with Castrol LSX90 diff oil. I have also tried spinning the wheels on grass, gravel, tar and mixtures of both and the wheels always spin easily (except on tar TD42 power). I am assuming my LSD is stuffed. Oh well another weekend in the shed for Aazz & Dad Mechanical.

you problem could be that you have put the wrong oil in it...should be LS140 ,not 90 !!

big red wrote:

aazz wrote:I have just got around to jacking up my car and it is an LSD. I then jacked up just one side of the car and spun the wheel. There was some resistance but the first revolution or when I first spun the wheel wasn't any harder than any other spin. I have changed the oil in the diff twice in about 500 kays, just to make sure, with Castrol LSX90 diff oil. I have also tried spinning the wheels on grass, gravel, tar and mixtures of both and the wheels always spin easily (except on tar TD42 power). I am assuming my LSD is stuffed. Oh well another weekend in the shed for Aazz & Dad Mechanical.

you problem could be that you have put the wrong oil in it...should be LS140 ,not 90 !!

At least it would be clean

The castrol container says the LSX90 is suitable for LSD's and the bloke at the shop said it is a good oil, the prick!
What brand is the LS140 oil I will try anything to get it to work again before I strip it down or put a locker in.

90 lsd oil will be ok.

Its only 90/140 to take the heat when the lsd is working hard.
Oil vis wont affect the lsd.
If you want it to grab use half lsd oil and half normal hypoid oil.

As I said earlier they dont just rely on the tension in the plates.
The pinions move very slightly and increase the loading on the plates under load.

Bazzle