Converting 10 spline to 24 disco 1 to disco 1

[brendan leier]

I'm considering picking up a used tru trac from a 24 spline.  Mine is 10.  Can I get away with stealing the half-shafts and hubs? I'm a little reluctas I just did my bearings and seals last summer.

[headdamage]

Assuming you have the thin drive flanges you just need the one piece half shafts and don't have to change hubs.

[brendan leier]

thanks, that's good news.  Front as well as far as you know?

[Red90]

thanks, that's good news.  Front as well as far as you know?

Probably not.  It depends.  I must assume this is a 200TDI era Discovery.  There were different axle configurations used through that period.  It is a bit of an involved discussion, because the later model 24 spline front axles are weaker than the 10 spline older axles.

[Matt H]

Anyone have a can opener? There is a tin of worms that is just about to be opened...

[brendan leier]

I kinda want to think this out before I make a choice.  I can get a couple used 24 spline trutrac diffs, actually not that cheap compared to new. I can also get new 10 spline truetracs each for $700.  Stock, neither 10 or 24 are inferior, but I am planning on running 235-85 tires and I understand it is nearly impossible to buy hardened 10 spline shafts, need be. So my choice is transition to 24 to improve the path to upgrade or replace half-shafts. I want to do read this year, front next. The cost seems less of an issue in this context compared to the hassle of breaking and sourcing 10 spline shafts. 

[Red90]

Get the 24 spline diffs. And then get aftermarket 24 spline halfshafts. The stock 24 spline shafts are quite weak.

It gives you a better system. Hopefully the fronts have the 23 spline CV joints. Those are a really nice design as they have short 10 spline shafts with integral flanges that go into the CVs. These are great fuses that are cheap and easy to swap out.

[Matt H]

I would also advise going to 24 spline, if for no other reason than all NAS spec Disco's being 1994 + models had them so replacements are easier to find. 94 & 95 RRC's too but they are getting harder to find these days.

FYI I've been running stock 24 spline axles in the Mighty Range Rover with double locked ARB air lockers and much fatter 285/75R16 tyres for years and have not had any issues. This truck has run epic sticky clay mud, super steep Rocky Mountain passes, loose scree, smaller rock gardens and Moab slick rock. Over the years I've found that sympathetic driving, more than HD parts, is the key to mechanical survival.

More often than not it's the stock differential that will let go before the axles anyway.

My 2c.

[Matt H]

Also, I would rather run a single rear ARB locker than two truetracs. It's a personal preference thing but I like that I can have the strength of the differential carrier full time but be able to turn the locker on and off as needed.


Just a thought.

[brendan leier]

I couldn't pass over the 24 spline diff, as it was new in box, never installed.  I've asked for his half shafts as well when the truck goes to Valhalla. I have time to watch land rover toolbox vids for a couple weeks to get properly psyched.

[Red90]

Just make sure it is setup for the axle it is going into.  The worm gears go in one way for a rear and another for a front.

All that aside, what is the story on this Disco of yours?

[Red90]

I I see in your sig.  A 92.  If working on the front axle, be careful on part numbers as they did a strange mid generation axle change in around that time.  Hopefully you have the earlier one.

[Red90]

Assuming you have the thin drive flanges you just need the one piece half shafts and don't have to change hubs.

Just double check things, as it was in the 92 model year that things changed....

Note the VIN change number in Ashcroft's chart: http://www.ashcroft-transmissions.co.uk/halfshafts.html  You need to be after JA032850.

[Matt H]

Might be worth getting a pair of axles from a dead North American disco and rebuilding them with the new true tracs? All parts will be standardized and easy to find and when you are ready you just swap in your nice shiny new/rebuilt axles complete!

You could then sell the 10 spline stuff on to recoupe some of the cost.

Just a thought.

[Red90]

Might be worth getting a pair of axles from a dead North American disco and rebuilding them with the new true tracs? All parts will be standardized and easy to find and when you are ready you just swap in your nice shiny new/rebuilt axles complete!

You could then sell the 10 spline stuff on to recoupe some of the cost.

Just a thought.

There are complexities to that idea.  The front brake setup is different (dual line versus single line).  The radius arms are different (narrow versus wide).  The rear pinion is different (rotoflex versus u-joint).  All the local Disco axles are rusty and worn out.