Outer Limits 4x4 Board

Guys
Want to fit Aisin manuals to HN 3.0 auto Super select to get the benefit of Low 2wd. Ive just read somewhere that if I do this I can't then shift from 2wd to 4wd while on the move (or will break somthing) if the hubs are unlocked (or locked for that matter) . Can anyone offer advice on problems this could cause (or would it work fine, apart from of course geting out to lock in when required) and how I should then operate/drive with them fitted.

Cheers
Mark

I'm making this up as I go along - let's see what happens.

If the hubs are locked, there's no difference to the existing setup - change to and from as per normal.

If the hubs are unlocked then the front driveshafts are not being road driven, and the crownwheel & pinion aren't turning either.

So what?

When you shift from 2H to 4H, two things happen.

First, the transfer case sends drive to the front prop shaft, so the pinion begins turning the crownwheel. So far, so good.

Second, the disconnect in the front right axle is released, to join the right axle to the diff. This could be a problem.

Nomally, with "locked" hubs, the front wheels are being driven at the same speed as the rear wheels. So, when the pinion drives the crownwheel and the left wheel drives the left axle, then the right axle has no choice but to be turning at basically the same speed, and the two halves of the front axle disconnect are travelling at basically the same speed - so engagement is smooth.

Now, unlock your hubs. The front wheels are no longer driving their axles, so we don't know the relative speeds of each axle, and we don't know the relative speed either side of the disconnect. So the disconnect could be trying to connect two shafts spinning at different speeds, which I'm guessing it won't enjoy.

I wouldn't expect instant catastrophic failure, but I wouldn't rule it out completely, either. More likely, each such engagement on the fly (but why would you bother?) will stress something in the system, and failure will occur some time in the future.

So, I would say there is a risk (of unknown size) in engaging 4H on the move with the front hubs unlocked - but I can't imagine why you would?

With the front hubs locked, the system won't know the difference. Will it? Lots of Paj owners have fitted manual hubs before, and I haven't heard of problems, so I'd say just do it!

Yea Scott's right, you just loose the 4H feature if you run them unlocked. Beauty is you can lock them then keep the 4H feature.

With having a centre diff, if you are in 4H it sends all the power to the front wheels are the vehicle doesn't move.

And you can't then put it in on the move as all the front drive train is stopped. If you try to put it in at 80km/h it willl result in some wonderful noises as the front driveshaft, diff and cv's go from 0 to 80km/h in a flash.

Cheers Guys
So if I get you right, I fit manual hubs, leave them locked and if I want to use for low 2wd just unlock at that time, however for the rest of the time leave them locked.
If I do this, although the hubs are locked and I am in 2H, as the transfer case is not engaging the front diff regardless theres no difference (the diff wont have any issues because its open centre; that said, is it now rotating when before it wasnt...i.e more wear?)

To add to the scenario, i've just picked up a v44 28splne diff to put a ARB into it in place of the small 25 jobbie (which no locker available) . If I fit the locker and am running in 2H with the hubs locked, again can you se any issues (i.e when the ARB is unlocked)?

Thanks again

I think I see your issue here. A Super Select Pajero doesn't have free-wheeling hubs of any form. The front diff is "disengaged" by disconnecting the front right driveshaft, which allows the diff sidegears to spin without spinning the crownwheel, pinion and front propshaft.

If you install manual free-wheeling hubs and keep them locked there is no difference to the operation of the Super Select system. It is only once the hubs are unlocked that anything changes.

Guys,
Found a set second hand, aparently off 88-89 model (thats the only info provided), are Aisin's model specific or will any p[ajero manual fit (note agaion these are for use on the v44 diff, but if that takes too long to sort I'd like to use on the v23 setup?

So long as they are 28 spline they should be fine. They look the same as mine.

Pajero and Triton Aisin manual hubs are all the same and are interchangeable.
The outer CV splines are all the same even the inner 25 spline CV's.
I had a set of Triton Aisins on my NJ 3.5 V6 - all good.