Spin out!!! LSD issues

[solarman216]

I accidentally put the wrong oil in mine recently and after a week I started getting slow speed noises at the rear end that I first thought to be a loose wheel, but was not, it was like driving over rumble strips slowly, after lots of playing about trying to find the problem and nothing, decided to change the oil again and instant difference, but it is in need of a change again as it was contaminated by the residues of the other oil and this is only after a couple of thousand miles, Rick

 

[Dynamics]

The fact that the LSD played up even after putting the correct oil in, says a lot about these units. There couldn't have been a great amount of the standard differential oil coated to the casing, cover and internals.

 

[lacroupade]

The fact that the LSD played up even after putting the correct oil in, says a lot about these units. There couldn't have been a great amount of the standard differential oil coated to the casing, cover and internals.

Any amount of standard oil will cause problems....its not just about any coating but the fact that you never get 100% out when you drain it, so theres still a fair bit to cock things up - its the diff equivalent of oil on your clutchplate...with the LSD it will, as said, cause the clutch packs to malfunction. The recommendation as Rick implies, for any unit with old or contaminated oil is to fill, run for a bit, then drain and refill a second time.

When properly filled with the correct LSD oil these units are utterly problem-free and help the T2 do things in 2WD that a L*nd R*ver can only dream about...

 

[Sparks61]

I have read everything in this thread but I am worried there is still something wrong with my T2. Long story short - last weekend I had an underwear changing moment involving a 400 yd stretch of water covered black ice and a 3ft slope into mud and long grass. Having recovered and checked all is ok I need to get my confidence back in the vehicle but it just seems SOOOOO tail happy.
I have changed the rear diff oil for the right stuff twice, it has brand new shocks all round, it has just had new front ARB bushes and drop links and it is running on a set of brand new Nokian Hakka 1 SUV winters with studs.
Today driving home from a day out I ended up on a wet gravel road climbing a hill with a little bit of power on (in third 4WD) and the SLIGHTEST disturbance on a bend (pothole; gravel mound) would prompt the back end to want to step out.
Bearing in mind the general nature of Iceland roads - i.e. always wet; often gravel; tram lined; potholed with f*****g great drops and no barriers - I am keen for this not to happen. Is there anything suspension wise which can cause it to be so unpredictable ? it is almost as if one small nudge sends it into an over centre condition.
As an idea of what an Icelandic road is outside the Reykjavik area see here. This is a single track admittedly but many "main" roads are like this but two lanes wide. This is a tame one as there isn't the obligatory 15 ft drop into a lava field on both sides

 

[lacroupade]

If I didn't know better (and sadly I don't) I'd say our 4WD wasn't working properly.

AFAIK its a 50/50 distribution front and rear in 4WD and while we expect the truck to be tail-happy in 2WD because of torque and the LSD, I'm sure thats not a normal thing to happen in 4WD, certainly never happened to me, even when doing a bit of car park 4WD drifting......

Be interesting to see if any of our - ahem - more adventurous members (Makeitfit springs to mind for some reason??:lol) have experienced the same phenomenon.....?

Apologies if this is an egg-sucking thing, but I assume your green 4WD light comes on, and that you've confirmed its definitely engaged by doing the "reverse on full lock on a dry surface" test which will have the transmission winding up and tyres scrabbling in no time (if its in 4WD).

 

[Sparks61]

No need to apologise the obvious stuff is always the best first thing to check. Yep the 4WD light comes on and although I haven't done the specific check you mention I do know reversing with any kind of lock on is difficult - like the handbrake is on and it "feels" like the transmission is locked (noticed it again yesterday turning round in a parking area down one of these gravel tracks.) so I think the 4WD is working. Did some non-scientific testing on a gravel carpark and it is better in 4WD but bonkers tail happy in 2WD. Even a steady increase in accelerator has the back end coming round - not talking booting it here, just accelerating as you would leaving a bend.
Any type of disturbance does seem to massively exaggerate it - as if it is on a knife edge and a pothole kicks it over. I'm thinking a bush gone somewhere allowing the geometry to change under load and causing loss of grip but I dunno :nenau

 

[lacroupade]

No need to apologise the obvious stuff is always the best first thing to check. Yep the 4WD light comes on and although I haven't done the specific check you mention I do know reversing with any kind of lock on is difficult - like the handbrake is on and it "feels" like the transmission is locked (noticed it again yesterday turning round in a parking area down one of these gravel tracks.) so I think the 4WD is working. Did some non-scientific testing on a gravel carpark and it is better in 4WD but bonkers tail happy in 2WD. Even a steady increase in accelerator has the back end coming round - not talking booting it here, just accelerating as you would leaving a bend.
Any type of disturbance does seem to massively exaggerate it - as if it is on a knife edge and a pothole kicks it over. I'm thinking a bush gone somewhere allowing the geometry to change under load and causing loss of grip but I dunno :nenau

Just weird! Makes no sense at all does it.....tyre dimensions and pressures the same front to rear?

4WD definitely sounds to be working fine.

What does it behave like in 2WD then....as you know, they are definitely tail happy if you apply too much throttle but if its less marked than the issue you have in 4WD there may be something amiss in the actual transmission system somehow....but don't ask me what.

Lets hope someone has some theories or experience.


EDIT: Just a thought. Whats it like in 4WD Low range? I have had the odd issue where the back loses a bit of traction in really slimy mud with too much throttle, mainly because theres a lot more weight on the front wheels than the back, but low range helps a lot in such situations....?

 

[geoffdown]

No need to apologise the obvious stuff is always the best first thing to check. Yep the 4WD light comes on and although I haven't done the specific check you mention I do know reversing with any kind of lock on is difficult - like the handbrake is on and it "feels" like the transmission is locked (noticed it again yesterday turning round in a parking area down one of these gravel tracks.) so I think the 4WD is working. Did some non-scientific testing on a gravel carpark and it is better in 4WD but bonkers tail happy in 2WD. Even a steady increase in accelerator has the back end coming round - not talking booting it here, just accelerating as you would leaving a bend.
Any type of disturbance does seem to massively exaggerate it - as if it is on a knife edge and a pothole kicks it over. I'm thinking a bush gone somewhere allowing the geometry to change under load and causing loss of grip but I dunno :nenau

Look in the manual and it tells u how many nm of torque u need to get the limited slip diff to slip urs might not be slipping at the right torque just an idea with mine jacked off the ground with 1rear wheel still on the ground if u try hard enough u can just about get the lsd to slip but it is hard work

 

[rustic]

Normally my response to this is have 2 identical tyres on the rear, both in depth of tread and pressure. but you have done that.

But if you are getting this slip in 4WD what are the front tyres like? since there is no central diff, something has to slip, and as said before, the front is heavier so the back is more likely to step out.

If it happens in 2wd then there could be some wear in the bushes, as your roads are generally more rugged than ours in the UK, although some would say ours are worse due to the speed humps and pot holes. :lol :lol
I would expect the wear and tear on your vehicle is greater than ours, I have never changed any bushes yet in 16+ years and 91 k miles, but some serious off roaders are changing them quite often.
I go off road every day, up the drive and into my garage. :augie

Also check the ARB bushes front and rear.
Also don't assume the worn bushes are at the back, worn bushes at the front can cause some issues.

I assume the wheels are on tight, bearings are ok and that the rims aren't buckled, it would be worth jacking it up by the rear diff and rotate the wheels, it might be something as simple as that. :nenau
Reason: if this has only happened since you got your new tyres.......


I hope you sort it.
Best regards, Rustic.

 

[rustic]

Look in the manual and it tells u how many nm of torque u need to get the limited slip diff to slip urs might not be slipping at the right torque

Which manual is this in, I didn't know the value existed.:nenau

If so... What is it, is it different for different models or production years?

The value must be quite a wide range as the wear and tear will affect it. Also the quality or cleanness of the oil.:nenau

 

[makeitfit]

I'd be inclined to bin the rear antiroll bar or at least disconnect one side :sly
I like the tailend happiness of the truck and use it frequently on tighter bends in the ruff , it really Ps off the landies :lol
The above suggested as it seems the road surface you're on most of time will allow the back end to get excited especially if you're a little bit lead hoofed
A more boring check might be the panhard bushes
Also assuming the rear shocks are good

 

[lacroupade]

I'd be inclined to bin the rear antiroll bar or at least disconnect one side :sly
I like the tailend happiness of the truck and use it frequently on tighter bends in the ruff , it really Ps off the landies :lol
The above suggested as it seems the road surface you're on most of time will allow the back end to get excited especially if you're a little bit lead hoofed
A more boring check might be the panhard bushes
Also assuming the rear shocks are good

I'd tend to agree with Pete (gawd help me) and its why I suggested trying the route in low range and see what happens....yes theres more torque being applied effectively, but with the gearing more than doubled, throttle response is much less aggressive and therefore more likely to help prevent breakaway.....

 

[Fez_uk]

it's light gravel, I think it's to be expected.

 

[makeitfit]

Ay :thumb2

 

[geoffdown]

Which manual is this in, I didn't know the value existed.:nenau

If so... What is it, is it different for different models or production years?

The value must be quite a wide range as the wear and tear will affect it. Also the quality or cleanness of the oil.:nenau

its in the main manual under PROPELLER SHAFT &
DIFFERENTIAL CARRIER section pd page 43 here is the info from that page hope that helps:thumbs



CHECKING DIFFERENTIAL TORQUE
Measure differential torque with Tool.
If it is not within the specifications, inspect components of limited
slip differential.
Differential torque:
353 - 392 N×m (36 - 40 kg-m, 260 - 289 ft-lb)
Assembly:
KV38105250
Tool number:
qA KV38105210
qB KV38105220

 

[rustic]

its in the main manual under PROPELLER SHAFT &
DIFFERENTIAL CARRIER section pd page 43 here is the info from that page hope that helps:thumbs



CHECKING DIFFERENTIAL TORQUE
Measure differential torque with Tool.
If it is not within the specifications, inspect components of limited
slip differential.
Differential torque:
353 - 392 N×m (36 - 40 kg-m, 260 - 289 ft-lb)
Assembly:
KV38105250
Tool number:
qA KV38105210
qB KV38105220

Thanks for that, I didn't know that's what it was meant to be..:doh
That's quite a tight tolerance within a 10% range, it should be possible to bodge up a rig to test that, a bit beyond the range of a home torque wrench, but a length of scaffold bar and some weights.....:nenau

If you can turn the road wheel by hand to test it then you must have had 3 shreaded wheat.:thumbs

 

[geoffdown]

Thanks for that, I didn't know that's what it was meant to be..:doh
That's quite a tight tolerance within a 10% range, it should be possible to bodge up a rig to test that, a bit beyond the range of a home torque wrench, but a length of scaffold bar and some weights.....:nenau

If you can turn the road wheel by hand to test it then you must have had 3 shreaded wheat.:thumbs

but thats the torque is at the hub nut so to speak not at the outer edge of the tyre so u have more leverage at the outer edge of the tyre does that make sense hope it does

 

[lacroupade]

but thats the torque is at the hub nut so to speak not at the outer edge of the tyre so u have more leverage at the outer edge of the tyre does that make sense hope it does

but thats still the equivalent of a ten-stone person stood on a 2-foot lever isn't it?.....

 

[rustic]

but thats still the equivalent of a ten-stone person stood on a 2-foot lever isn't it?.....

Well my lever wouldn't have to be as long as that...

My scales speak your weight and they say "One at at time PLEEEEEASSSE"

Or after Christmas, " No Coach Parties" :lol :lol

So this weekend we will all be lifting one wheel off the ground and trying to turn it :bow:bow maybe not :lol

 

[lacroupade]

Well my lever wouldn't have to be as long as that...

My scales speak your weight and they say "One at at time PLEEEEEASSSE"

Or after Christmas, " No Coach Parties" :lol :lol

So this weekend we will all be lifting one wheel off the ground and trying to turn it :bow:bow maybe not :lol

Note I said 'person' LOL! :augie