Thread: Ashcroft ATB Center Diff for 2013 PUMA

...so pardon my ignorance: can you still lock the centre diff with a centre ATB fitted?

Originally Posted by skidrov

...so pardon my ignorance: can you still lock the centre diff with a centre ATB fitted?

Yes

Originally Posted by inken_dave

Does anybody have any firsthand experience of a Ashcroft gearbox adaptor shaft failing?

No but mine has a very small oil leak from the GBox, which seems not able to be resolved so far.

Mine has been in for the last 40K, will be replacing the clutch next service (130K) so I'll have it checked and have the seals checked when I get that done.

Cheers Glen

Originally Posted by rick130

I suppose if at least one wheel had traction at either end it would, but as soon as that wheel lost traction the centre diff would act as an open diff

Yeah, that's what I was thinking as well.... as long as u keep one wheel on the ground Front & Rear it should be fine but not sure if it would be good for the ATB long term.....

What I have read, and mixed in with some common sense, is to treat the transfer box as you would a standard unit. Think of it as an up-rated centre diff.

In this order as conditions deteriorate:

4x4 Hi Range, open centre
4x4 Hi Range, locked centre
4x4 Low Range, Locked/unlocked centre depending on ground speed required
4x4 Low Range Locked centre
4x4 Low Range Locked centre + locked rear
4x4 Low Range Locked centre + locked rear + locked front


The ATB diff really works for keeping even pressure on both axels during dirt road driving. It stops either axel from having a bias.

And as a bonus, which has been said before, the best feature is the complete removal of any backlash in the tx case! Mine was horrible! Drives really well.

...just an observation... if you don’t have at least one wheel on the ground you’re flying LOL.
And I would have thought that at least two wheels on the ground would be the minimum for keeping her shiny side up!

My understanding is that ATB’s constantly redirect torque to the wheel not slipping on all surfaces, whilst maintaining the benefits of an open diff (IE allowing a modicum of slip so less likely to break something). I think of an ATB it as the best type of LSD available. Works particularly well with traction control.

Installing an ATB in the centre / TC ‘diff’ is a unique Land Rover attribute, enabling the above benefits front to rear constantly on all surfaces, preventing any hard surface wind-up in TC + strengthening the TC + TC can also still be fully locked. Best of all worlds.

Obviously a diff locker enables zero wheel slip across an axle / between two wheels, but more likely to break if pushed hard

I've had my ATB for a while now.

The bid advantage is with two situations applicable to my driving.

Manoeuvring say a trailer load of firewood in low range. You don't want to lock the diff 'cause that causes tyre scrub & this means mechanical stress. ATB gives a bit of slip (1/4 turn of a wheel normally) and then grip.

Driving on graded dirt roads, especially with pea gravel. The ATB stops the traction losing torque shuffle over the piles of stones if you leave the centre diff unlocked. Whereas locking the centre diff promotes understeer.

The atb would be good if you are unloading boats, driving on snowy tarmac, outback gravel roads - all up it's all positive, and when you consider the reduction in drivetrain backlash and no need to replace the thrust washers it all adds up to a great mod.

You just lock it up the diff as per normal on true low range 4wd tracks.

Clive

I don't think a centre diff atb is unique. A block at works new Prado Kakadu has exactly this arrangement. There maybe others 4wds with this too.