Transfer Case not locking centre diff.

[benji]

I'm after some collective wisdom as to whether this is normal or not.

In essence it will allow the front to spin, without directing torque to the rear axle.
I'd normally suspect the vc in this case, however it's a brand new vc, and its exhibiting the same characteristics as the one I pulled out. My previous p38 I also had problems with in this regard to a lesser extent, though I was roughly 100kg heavier on the front too.

Even with the seemingly open centre diff, it'll still do double black diamond tracks in the high country, though on very steep tracks it does get loose in the front end and I really have to drive it hard.
I do have a vid of it, but it's to large to upload - however the front with spin at around 15kph before it directs enough torque to spin the rear (I usually have the rear locker on so I can see it from the drivers seat).

I did put it up on facebook, but I'm finding it a baby sitting exercise whereby I'm explaining how diff works and that they don't run the lt230.

I'm just after an opinion from those that use these offroad wether that amount of spin is normal or not - in my mind it shouldnt be.

Benji.

[Keithy P38]

In my dealings with P38’s, it’s not normal. And you know how I drive mine ;-)

I would say that mine almost immediately locks when wheels start lifting, the traction control usually lets you know when wheels are slipping (although yours is rear only traction control from memory?).

A few factors can influence the drive ratio, perhaps one of these is relevant and maybe worth trying in your case?

Tyre pressure bias - Running them equal pressures when loaded will send a rear bias due to slightly larger rolling diameter up front with generally less weight up that end. In my case, I need to drop to 18psi up front and run about 22psi out back when loaded (on 18’s) to have roughly equal footprint.

Temperature - Similarly, a slight bias in pressures (and thus equal footprint) will keep the VC fluid cool, potentially taking longer for the VC to do its thing. Ideally, a slight front bias is a good thing for 4wding, as it’ll then transfer drive to the rear - where the weight is.

I hope this helps, and maybe gives you something to play with to see if it makes a difference!

Cheers
Keithy

[benji]

Thanks so much, yes you certainly don't hold back which is good.
Another bloke in WA had also said his behaves very differently too. He's taken forage of his climbing his front garden with the rear locker in and you can see the vc reached its lockup point pretty much instantly. Certainly within half a second it gave solid drive to the rear.

Mine has sn initial stiff point then it just goes almost open and I wouldn't mind betting is the friction from the planetary in the diff that's sending torque to the rear.

I'm still slightly confused from Rave regarding how the center diff works, but in essence I think it's a conventional planetery open diff. With the vcu directing drive into the forward nose of the rear output shaft.

Thanks again👍