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Ashcroft ATB on road

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I'm thinking about fitting the Ashcroft ATB diffs in the front and rear of one and maybe both of my 110s. I'll probably do the Tdi first, and if they seem to make a worthwhile difference I may do the Puma as well, as it's out of warranty in a week so I can start fitting interesting bits :)

However, I'm keen to know what people's experiences are of using them on-road. Due to being in the Falklands most of the roads here are loose gravel / graded clay and any 'odd handling characteristics' might be magnified. I don't want to end up with a vehicle that wants to swap ends without warning on loose corners. I also don't want to have a vehicle that routinely makes graunchy diff noises going round corners in town, because non-standard noises drive me around the twist.

I have not recently done a thorough search but I think I have seen comments that say there are no effects at all and other comments that there are some noticeable effects on cornering. I don't have a feel for whether this is different between SWB and LWB vehicles, both of mine are 110s.

Any views from owners that have used them for a while on and off road please? I'm interested in both performance off-road and any side effects on-road, as both matter.

The diff centres themselves appear excellent value and being Ashcroft I am sure that they are well made, but I have zero experience of gear-type LSDs, my only experience is with the ones fitted in the back of Mitsubishi/Ford pickups which on the whole are pretty useless but they are plate-type LSDs. Everything I see says that the gear-type LSDs are a different animal and much more effective.

I don't want the cost or hassle of fitting full lockers and the type of issue I'm trying to solve is to improve climbing performance on steep/loose/slippy surfaces or boggy ground, where I think a gear-type LSD will control wheelspin and keep all four wheels moving where a standard vehicle will often spin on opposite corners. I'm just trying to figure out if there are downsides and whether they are likely to annoy me...

Ta :)

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Just do it (like Nike :D ) There are no mentionable downsides to running them on the road or Loose surfaces, I would actually say to the contrary. If you drive like a hoonigan it will slide a bit easier but the slide is then much easier to control than with open diffs. There's no banging or snapping or any kind of jolting in the steering-wheel everyting feels smooth and natural. If only they were fitted to LRs as standard they would've sold soo much better as there are none of the ill effects of the clutch type LSD's of the Japanese pickups

Edited by Soren Frimodt
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If you are really fussy, you will notice them in the front.  It is not "bad", but you can tell.  They tend to self center under power a small amount.  Also, if there is any variation in tire pressure side to side, the steering will pull to the low side.

In the rear, you will not notice it is there.

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From what I have read, Bo, on here and a lot of other places, they seem ideal for what you want, not dissimilar from me.  Locked diffs can force a skid when cornering, whereas these shouldn't.  So, they have the benefits of keeping you going through slippery conditions without fighting steering and cornering as much.  From what I understand, they are better for the shafts, too, not snatching as much.  The negative complaints seem to be from those who don't understand how they work, needing a little left foot braking on non-ETC vehicles if a wheel is in the air.  The nay-sayers seem to expect them to behave like automatically locking diffs.

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Incidentally, if you fit any kind of locker or LSD/ATB in the front, it would seem that upgrading the front shafts and CV joints is a necessity as the CV ends of the shafts are too skinny and snap easily.  I don't know if that applies as well to slippery road use like you have as it does to proper off off-roading, but Nige is pretty convincing in his comments on the matter.  Rear is less of a problem.

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Ta. I drive it sympathetically off-road and have never broken a halfshaft or CV, though a couple of 2-pin diffs have been ... modified. I don't want to upgrade all the front end, which is part of the reason for going for ATB rather than full locker. Most of the situations that get you stuck in off-road conditions here are simply overall lack of traction rather than trying to winch up a cliff, the challenge is usually getting up wet slimy peat-covered hillsides etc so the absolute component load is not too threatening, it's just the lack of grip that makes the most lightly-laden wheels start to spin.

As for "proper off roading", trust me you can do plenty of that without endangering standard parts :)

DSCF3106.thumb.JPG.4e2dbad8d8f281ecc711dd1c428dedc8.JPG

 

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If you have the 32 spline CVs, it is really not a good idea to leave them in there.  They are very small at the inlet to the CV.

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I hope Nige doesn't mind me posting up this link.

There is a big difference in the amount of torque the shafts will be loaded with when comparing your type of driving to comp safari or even soft sand driving.  Whether it is within or without the capabilities of the standard shafts is not something I have any knowledge of.  I have older ales with the 10 spline diffs.  The CV end is strong, but the diff end of the shafts snap, common on Series back axles.  They're far stronger than the later axles' shafts, and several people have assured me it's worth upgrading.  I'm fortunate that it's just the shafts that need upgrades, not CVs, stub axles and so on.  But my RRC has the same front axle as yours, and would be equally expensive to upgrade.

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Interesting video, hadn't seen that before. Quite a difference between the types. My Tdi is a 2006 (very last of the export Tdi engines) so I presume it'll have the 32-spline CV.

I guess the issue is that the cost goes from £700 odd to a nasty hole in a couple of grand by the time a new set of CVs and shafts is added, which is probably more than I'm prepared to spend at the present time.

I do know of folks here with full ARB lockers and there isn't (based on 15 years managing a workshop) a long history of people breaking the newer CV joints as far as I remember, even on ARB-equipped vehicles. So I take the point about the weakness, but might accept it and try it anyway. I'll ponder a little longer. Thanks :)

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Happy you posted my video Sir ...I refrain as its a tricky conflict of interest being an Admin here and running a Differential Business !.

To err on the side of caution I rarely will post up anything here contentious for that reason, best safe etc.

 

As to ATB. Ashcroft are very good. Stunning value and a 3rd of the quaife unit which is very very similar. For your purposes Ashcroft are more than enough.

 

Points

 

1. they can sometimes add more transmission noise than an open diff.

2, You REALLy will need to up grade to 23/24 shafts and CVs whilst ashcroft stuff would be nice, backward fitting earlier standard 23 CVs and half shafts would be a huge strength increase

3. run EP90 no special oils a la LSD stuff needed

4. Oil changes are a must and regularly, damage to centres often turns unit to scrap due to the amount of gears in there, spares are minimal often as I say damage = new unit

5. Front axle will feel as if you have low tyre pressures but you will adjust and learn

 

Nige

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Here is my chart with the numbers showing the size and relative strength of the different spline sizes.

calulations.jpg

One of the things you need to watch is that the stock later model 24 spline shafts are waisted to give them around the same strength as a 10 spline shaft.

Disco 1 Rear 24 spline shaft. 27.4 mm waisted section. 

Rover_Rr_24.jpg

It needs to be 30 mm to be as strong as the splines, like this Salisbury 24 spline rear shaft.

Sals_24.jpg

Edited by Red90

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9 hours ago, Hybrid_From_Hell said:

Points

1. they can sometimes add more transmission noise than an open diff.

2, You REALLy will need to up grade to 23/24 shafts and CVs whilst ashcroft stuff would be nice, backward fitting earlier standard 23 CVs and half shafts would be a huge strength increase

3. run EP90 no special oils a la LSD stuff needed

4. Oil changes are a must and regularly, damage to centres often turns unit to scrap due to the amount of gears in there, spares are minimal often as I say damage = new unit

5. Front axle will feel as if you have low tyre pressures but you will adjust and learn

 

Ta Mr Hell :)

What sort of noise? Just on cornering, or all the time?

What do you mean when you say it will feel like low tyre pressures - heavier steering, or something else?

One option might be to just do the rear. Are they 'handed' or should I say 'ended' - i.e. with bias for either front or rear axle?

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As mentioned earlier, under power, the self centering is stronger when in a front axle.  You only really notice if you drive it back to back with an open diff.

The True-Tracs are front and rear, you can change them yourself, if needed.  You need to turn the worm gears around.  It is because the worm gears only have a thrust bearing in one direction.  The Ashcroft works both ways.

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What I should also have mentioned is that the ATB also seems like an excellent way to get rid of a standard 2-pin diff centre in the front axle, which is something I also want to do as it's the only axle part that has ever given me trouble over the years. So the alternative is not to do nothing, but to fit a 4 pin centre which is nearly the same cost anyway (£260 vs £335).

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On 30/05/2018 at 9:57 PM, Hybrid_From_Hell said:

Happy you posted my video Sir ...I refrain as its a tricky conflict of interest being an Admin here and running a Differential Business !.

To err on the side of caution I rarely will post up anything here contentious for that reason, best safe etc.

 

As to ATB. Ashcroft are very good. Stunning value and a 3rd of the quaife unit which is very very similar. For your purposes Ashcroft are more than enough.

 

Points

 

1. they can sometimes add more transmission noise than an open diff.

2, You REALLy will need to up grade to 23/24 shafts and CVs whilst ashcroft stuff would be nice, backward fitting earlier standard 23 CVs and half shafts would be a huge strength increase

3. run EP90 no special oils a la LSD stuff needed

4. Oil changes are a must and regularly, damage to centres often turns unit to scrap due to the amount of gears in there, spares are minimal often as I say damage = new unit

5. Front axle will feel as if you have low tyre pressures but you will adjust and learn

 

Nige

Just an adjunct to Nige's post, I'd run a 75W-90 just to ensure you are getting decent oil feed inside the ATB case at temps below normal operating temp.

As mentioned there are 6 helical planetary gears running in pockets inside the case and oil feed may be compromised at high speed with a viscous oil, eg an SAE90 at least until it's up to operating temp.

If you're careful and take a few km to get things warm before running the diff at motorway+ type speeds an EP90 wouldn't be an issue.

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Didn't LR change the standard spec in later Defenders to 75w anyway, or am I mixing it up with something else?

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I've a Trutrac in the back axle. Not a locker, so if you lift a wheel you're still stuck (or you'll be left-foot braking), but if it's slimey or on gravel you'll see a little more grip.

 

The only negative I can assess is that, when cornering hard enough that the inner rear wheel might slip a little, it'll push from the outside rear wheel instead which gives you a shove around the corner but tends to tighten the line, feeling like oversteer. It's only just noticeable, enough that I'm not sure it's not just 'tuck' on the rear trailing links geometry or similar, but the ATB would explain it.

It's no locker, but it's a great budget option.

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You should be able to notice the diffs on road. But may not. Depends how you drive really. 

Fwd cars like a Honda DC2 Integra Type R or Rover 200 BRM have front TorSen diffs that work largely the same as the Ashcroft units. You really can feel the diffs working in those vehciles. Which when under cornering make them tuck in tighter in the bends. Rather than push wide. They also reduced one wheel spin (usually inside wheel). This happens less with 4wd but is still possible in a Land Rover with open diffs. 

At the rear it will just be like any other 4wd/rwd car. And again reduce inside rear wheel spin. Cars like a Subaru Impreza run a centre and rear LSD. 

Overall the ATB’s should be better in every situation. Be it on road, gravel or proper off roading. But you should feel the front one through the steering a little. But not in a bad way. 

If you are going to the cost of getting these and you do a lot of gravel road driving I’d be tempted to look at the LT230 ATB also. 

As for off road use. My Uncle has the ATB’s front and rear in his 90. It will walk through axle twisters that can stop open diffed 90’s. 

This is a slow mo of my brothers 90 on a good axle twister. If you go too slow it’ll stop it quite easily. The 90 with the ATB’s has less suspension travel and doesn’t flex as well. But will literally drive through on tickover without being stopped. You can just feel as the diffs kick in. 

Sorry no vid of the ATB’s in action yet. 

 

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A question has arisen as I prepare to get the job done....

Does anybody know of an overhaul manual existing for the P38 short nose diff, as fitted to the back of a post-2002 110? I have torque settings and the overhaul manual for the standard long nose diff, courtesy of Ashcroft (it's in an old Land Rover workshop manual along with the full diff setup procedure, from back in the good old days when the factory wrote proper workshop manuals). However it is too old to cover the P38 diff (it has a 4 pin HD diff but I am pretty sure it will be the 4 pin long nose as fitted to Camel Discoverys and the back of some V8 90s).

The info I need in particular is

i) whether the crownwheel bolts are a different torque (probably not as they are the same size - standard diff is 58nm)

ii) whether there is a different torque setting for the side bearing caps (standard is 90nm)

iii) whether there is any difference in the setup procedure to the long nose diffs in terms of setting backlash (standard process is tighten the crownwheel side until all backlash is removed and then tighten the opposite side until the specified amount is obtained)

In the absence of better info I will just use the info for the standard diff but it may or may not be appropriate. Land Rover of course say that the P38 diff is 'non serviceable' but somewhere there must exist the settings used on original manufacture. Has anybody got these squirreled away somewhere? My thought process at present is that as the crownwheel bolts and the bearings are apparently the same, the torque settings will probably be the same.

Ta :)

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He might but I think he's too busy welding :lol:

I guess there is no 'official' overhaul manual for these diffs but the start of the P38s is just about far enough back that they still wrote real manuals rather than the "This is a non serviceable part" which is in too many places on modern vehicles. In fact the manual for the Discovery 5 is just one page which says "This is a non serviceable item" :lol:

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Ah, Mr Ashcroft has just come up trumps with an extract from a manual that I've never seen before, so I'm sorted :)

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At least you're sorted but Nige would definitely know. At least I hope he does :ph34r: as he built my pegged short nose Ashlocker for the back of my 110.

Haven't broken that yet, snapped a crankshaft but don't think that's his fault...

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Pegged short nose? I thought I watched a video yesterday saying that it wasn't possible to peg a short nose diff because there wasn't space in the casing :blink:

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That's what everyone thought, even Ashcrofts at the time. Turns out Nige is a bit stubborn and doesn't think like everyone else :hysterical:. It is a blooming tight fit though.

He'd done a trial with a 4 pin before and I've got his first pegged short nose Ashlocker.

He did say it is a little scary taking a brand new shiny locker from the packaging and then putting it straight in the lathe...

Ashcrofts still honour the warranty because it's been done by him but I've had no need to try it.

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