Gen 3 rear diff binding when hot

[dannyv68]

Hi all, hoping someone can assist here.

I have 2001 swb auto shogun/pajero.

After I've been on tarmac and the rear diff warmed up it will bind when I turn the vehicle and the diff has to work.

It goes away for a while if I put fresh oil in the diff but then within a few journeys its back binding again.

It's a bit less noticeable when in 4wd.

One suggestion I have had is that the diff lock is trying to engage - so an actuator/vacuum issue.

I've swapped the diff out twice now and its aw
Always the same pattern, ok until its had a journey at goodctarmac speeds, 70mph, then it will bind on turns. You cant feel the binding when turning at speed but I guess the issue us still there there are just bigger forces at play

Really appreciate any advice or if anyone knows a gen 3 guru garage in the UK.

Thanks in advance.

Dan.

[old Jack]

Hi Dan,

I think you need to see a diff specialist and get the pinion and crown wheel backlash checked.
It could be the pinion is meshing to far in on the crown wheel.
When you are swapping diffs over are they the same ratio and are you swapping diff pumpkin assemblies or are swapping out diff centres and using the same CW&P's ?

OJ.

[erad]

Do you have a rear diff locker or limited slip diff? If you have a LSD, you may have the wrong oil in the diff.

[El_Freddo]

^ this. LSD and wrong oil, or an issue with the LSD.

If you have a rear air locker it’s not vacuum that’s used (if it’s like the later models which I dare say it will be), there’s a little air compressor that activates to hold about 8psi IIRC from what I’ve read about them. I’d love to have one of these in my NP.

All the best with it.

Cheers

Bennie

[psproule]

It wont be wrong oil if its the LSD as they are a Torsen hybrid (viscous coupling) LSD. They dont actually run LSD oil as there are no clutches or cones. But even if you do run LSD oil it actually doesnt matter. It could be the viscous coupling (VCU) binding. They are designed to do that as the friction generates heat and changes the viscosity of the fluid in the coupling to add preeload to the Torsen gearset. VCU's can go off though, usually with the fluid going hard or very thick. Very common in Freelander 1's where the centre driveshaft VCU locks up making them bind in turns. Pajeros also run a VCU in the transfer case for 4H mode.

Pat

[dannyv68]

Massive thanks for the replies

So when I ve swapped diffs its the right ratio and the whole diff with companion shafts, locker etc. I've not taken any bits of LG inside.

It's not LSD, it has a separate diff locker.

The fact its done it on three different diffs ve tried now makes wonder about whether it is an issue with the air supply to the diff lock. It engages and disengages cleanly according to the dash lamp.

All three diffs I have tried have seen a bit of action but all off different vehicles.

I didnt quite follow the viscous coupling bit - that's inside the rear diff?

I've ordered some American Lucas heavy duty diff oil of the right spec but there is something going on.

I dont think there is any way it can be the transfer box as it gets better for a bit when you change the diff oil.

Appreciate all the help

Anyone ever heard of this at all?


Thsnks all.


Dan.

[psproule]

If its a factory diff lock it does not have a torsen and viscous coupling.

Pat

[Keithyv]

2001 so it’s going to be 4wd on demand or is that vintage Pajero Super Select?
I’m just wondering if you are driving in 4wd (locked centre diff) somehow when on tarmac?

[Having Fun]

2001 so it’s going to be 4wd on demand or is that vintage Pajero Super Select?
I’m just wondering if you are driving in 4wd (locked centre diff) somehow when on tarmac?

+1

[dannyv68]

Hi, yes you have to select it, theres no traction control o relectronic wizardry it's either 2 or 4, 4 with centre lock, hi lo etc

I think if centre lock was in it would be really hard to turn at all wouldnt it, like having rear diff lock on driving on a grippy surface, its and interesting one though - thanks for the thought, I'll mull it over and see if I can check that it is coming out of centre lock- the lights say it is.