LT230 ATB

[Chicken Drumstick]

Just wondering if anyone on here has got or used the Ascroft ATB limited slip diff for the LT230 transfer box?

http://www.ashcroft-transmissions.co.uk/index.php?act=viewProd&productId=381

[landroversforever]

I've got one in the transferbox in my build.... not yet used it obviously!

What are you wanting to know? I went for it as I'm likely to spin a wheel now and then, and it means I still have the option to lock it fully.

[Chicken Drumstick]

Wondered how it compared to the viscous unit in a Range Rover off road. And how much it removes the need to lock the diff on difficult terrain. As in theory it should allow for a tighter turning circle than having the diff locked. 

[V8 Freak]

I have one fitted and to be very honest I've not noticed any difference...

Last year on a twisty climb out of Andorra at a point where either momentum or a locked centre diff would have normally been used. I slowed and didn't lock the centre diff.... The truck stopped as it would without an ATB.

One wheel in the air only on the front axle. Rear axle has an Ashcroft ATB/LSD and front is open diff.

Centre diff locked, backed down a little and went back at the same point and rolled on though even though the same wheel lifted.

This may not be the intended use and I still only lock the centre diff when i think it will be needed and not like some advocate "always locked when off-road"

I don't know if this is the intended use for the ATB but I've no really noticed its there... Not sure i would notice if removed !

Neil

[landroversforever]

Do ATBs need to have some load on the 'unloaded' side to be able to transfer the power?

I'm trying to remember what was in a whitbread buggy at Billing a few years ago... that had some kind of LSD in both ends and wouldn't drive with two wheels off the ground.

 

[Ed Poore]

17 hours ago, landroversforever said:

Do ATBs need to have some load on the 'unloaded' side to be able to transfer the power?

I'm 99% sure that is the case. You can try to overcome this with cadence braking but the same is true of an open diff.

[SteveG]

I'd be personally inclined to spend the money on putting one in the rear diff. This will give you the biggest return for your money. 

 

[o_teunico]

 Detroit Truetrac, I think same type a of locking as ATB. In this case mounted in axles.

[Snagger]

On 05/07/2017 at 0:44 PM, V8 Freak said:

I have one fitted and to be very honest I've not noticed any difference...

Last year on a twisty climb out of Andorra at a point where either momentum or a locked centre diff would have normally been used. I slowed and didn't lock the centre diff.... The truck stopped as it would without an ATB.

One wheel in the air only on the front axle. Rear axle has an Ashcroft ATB/LSD and front is open diff.

Centre diff locked, backed down a little and went back at the same point and rolled on though even though the same wheel lifted.

This may not be the intended use and I still only lock the centre diff when i think it will be needed and not like some advocate "always locked when off-road"

I don't know if this is the intended use for the ATB but I've no really noticed its there... Not sure i would notice if removed !

Neil

ATBs behave like open diffs if one wheel loses all resistance.  You need a small dab on the brakes to fool the ATB, and then it will give its maximum output to the other wheel.  ETC would work wonders with ATBs, doing the initial brake jab on just the one wheel and then backing off until normal service resumes, rather than continuously slowing the wheel and sapping power (and wearing the pads and disc).  They don't behave quite like LSDs or viscous couplings, which don't need the momentary brake input.

[Chicken Drumstick]

On 08/07/2017 at 7:58 PM, SteveG said:

I'd be personally inclined to spend the money on putting one in the rear diff. This will give you the biggest return for your money. 

 

Not allowed for trials competitions. 

[Dave W]

I trialled for a while with ATB (Quaife) diffs in my Range Rover and they gave no advantage whatsoever so I replaced them with air locking diffs instead so at least I knew what they would do and when. The only advantage, to me, is their strength and I think that's where the ATB Transfer boxes are being sold.

You really need to know when it's locked and when it isn't and I suspect you'd get more joy by making sure your "manual" diff lock engages and releases smoothly so you can put the diff lock in/out mid section as required.

I also tried a Borg Warner transfer box at one point but other than being stronger (in that you couldn't kill it by forgetting to put the diff lock in) it didn't give any advantage and not being able to flip the diff lock in and out when required was frustrating sometimes.

[Chicken Drumstick]

The Borg Warner doesn't need a diff lock as it never really fully locks. That's the beauty of it for a trials Vehcile. It'll keep both propshafts rotating but will allow them to rotate at different speeds. 

A classic Range Rover with one will generally turn significantly tighter than a Disco 1 with an LT230 and a locked centre diff. Despite the same axles and wheelbase.

And of course you can use the handbrake on the Borg Warner and lock the rear wheels. Whereas on an LT230 you need to take the diff lock out first and then remember/have time to put it back in again after using the hand brake. 

My thoughts where along the lines of, would an ATB LT230 drive like the Borg Warner off road without the need to lock the LT230's diff lock. 

However thinking on it. Maybe it would only work if you could keep all 4 wheels on the ground. Lifting a single wheel might be enough to upset the apple cart. A TCS equipped Defender would probably work well with it however. 

[Dave W]

I've never been fully convinced by the BW thing. From driving them and repairing them it always seems to me that the perceived view (as described in the advertising literature) is that it locks up when needed but the reality is the opposite to that, it actually releases when it reaches a set torque front to rear and is, otherwise, permanently locked. When they go wrong they tend to stop releasing altogether, staying permanently locked even when the torque across them exceeds the set point where it should release to avoid wind up.

I tried the transmission brake thing but never had much success with it, there were always a lot of different theories about the potential or otherwise of the BW box but in side by side comparisons there was never a clear cut outcome that suggested the BW gave any competitive advantage other than it's strength. I think you probably get a bigger advantage by using larger diameter tyres on the front axle which you don't want to do with a BW box really.

What I'd really like is a mod to the LT230 that lets you precisely control the diff lock, maybe replacing the mechanism with a solenoid with a more positive engagement and disengagement. In my perfect world I would then have a control button that, in trials mode, would release the diff lock while pressed and reengage it as soon as I let go of the button so that during "safe" tight turns I can flick it out and no that it will disengage and then, more importantly, it will instantly reengage rather than engaging 5 seconds after I needed it !

I did toy with the idea of an Atlas 2 speed box as that gives the positive control, in low range at least, of sending drive to either axle or both axles as required so you can shift either axle into neutral while driving the other axle. If I were competing more seriously that would be my preferred route, maybe even an Atlas 4 if I was feeling really wealthy...

[discomikey]

The main advantage of an ATB diff is not low speed technical off road driving where lockers or spools are the most effective but high speed off road where grip characteristics are improved and therefore the vehicles become more predictable on cornering. 

I've run an ATB rear on road, off road and high speed and they are definitely advantageous. They are better slow off road than an open diff if you left foot brake to aid it bias. It acts like an open diff with no preload.

[Snagger]

Very interesting stuff.  

It seems like for hard core off roading, full lockers are still best, at least in the back end, but for all weather, laning and expedition use, ATBs offer better characteristics, less likely to cause a skid on wet grass or on snowy/icy roads.  

I've been reading around, because I quite fancy them, and there seem to be three brands available for LRs.  Quaife, Eaton and Ashcroft.  The Quaifes appear best, even Ashcroft stating so, but are very costly.  Eaton are second dearest, but appear lower quality than Ashcroft, especially now they're built int he far east, with quite a few stories about spectacular failures.  They only have three worm gear sets, while the other two have six pairs each, so I can't help but think that must affect longevity and also the amount of control they exert.  The bias ratio has been said by Quaife and Ashcroft to be misleading and irrelevant, but I still have my suspicions that the Ashcroft must perform significantly better than Trutracs. 

It's a shame that Ashcroft don't do a Salisbury axle version.  I wonder if the difference in longevity and performance between an Eaton and a Quaife justifies the price difference - for the same money, you can do the front diff, and that is presumably be a better option than the higher spec rear unit alone for those who aren't doing extreme off roading, but I do wonder.  Anybody got experiences they can share?  Nige's views on the quality and robustness would be very welcome; his previous recommendation for Rover axles was explicitly clear to go for the Ashcroft, even if that meant getting uprated shafts (not a lot dearer than a Trutrac anyway).

I'd love a pair of Ashcroft units in my RRC when it gets done, but given the need for upgrading the shafts and CVs, with all that entails, it Looks like I'll just have to stick with the rear ETC.  It only gets used on road, so the all weather ability is already good enough for most conditions.

[landroversforever]

1 hour ago, Snagger said:

Very interesting stuff.  

It seems like for hard core off roading, full lockers are still best, at least in the back end, but for all weather, laning and expedition use, ATBs offer better characteristics, less likely to cause a skid on wet grass or on snowy/icy roads.  

I've been reading around, because I quite fancy them, and there seem to be three brands available for LRs.  Quaife, Eaton and Ashcroft.  The Quaifes appear best, even Ashcroft stating so, but are very costly.  Eaton are second dearest, but appear lower quality than Ashcroft, especially now they're built int he far east, with quite a few stories about spectacular failures.  They only have three worm gear sets, while the other two have six pairs each, so I can't help but think that must affect longevity and also the amount of control they exert.  The bias ratio has been said by Quaife and Ashcroft to be misleading and irrelevant, but I still have my suspicions that the Ashcroft must perform significantly better than Trutracs. 

It's a shame that Ashcroft don't do a Salisbury axle version.  I wonder if the difference in longevity and performance between an Eaton and a Quaife justifies the price difference - for the same money, you can do the front diff, and that is presumably be a better option than the higher spec rear unit alone for those who aren't doing extreme off roading, but I do wonder.  Anybody got experiences they can share?  Nige's views on the quality and robustness would be very welcome; his previous recommendation for Rover axles was explicitly clear to go for the Ashcroft, even if that meant getting uprated shafts (not a lot dearer than a Trutrac anyway).

I'd love a pair of Ashcroft units in my RRC when it gets done, but given the need for upgrading the shafts and CVs, with all that entails, it Looks like I'll just have to stick with the rear ETC.  It only gets used on road, so the all weather ability is already good enough for most conditions.

If your RRC is 24 spline already, I wouldn't worry about upgrading the shafts straight away. I had a locker in the back of the 90 running some random RRC shafts and didn't break anything.

[Ex Member]

Just go by cost.  I've never heard of a True-Trac wearing out or breaking unless you let the lube get dirty.  It certainly never would in a Salisbury.  Their biggest design deficiency is not having a thrust bearing for use in reverse.  Only a problem is you drive around in reverse all the time...  The number of worm gears is not an issue as the 3 pairs are bigger than the 6 pairs....   For new, the Ashcroft is the best choice.  I have a True-Trac.  I've always been able to find them used for very little money.

[Snagger]

3 hours ago, landroversforever said:

If your RRC is 24 spline already, I wouldn't worry about upgrading the shafts straight away. I had a locker in the back of the 90 running some random RRC shafts and didn't break anything.

The problem is the front shafts - the CV ends are very thin and, to quote Nige and his excellent half shaft video, "snap like carrots"!  I could put one in the back, but the ETC is probably enough for winter roads.

[Snagger]

1 hour ago, Red90 said:

Just go by cost.  I've never heard of a True-Trac wearing out or breaking unless you let the lube get dirty.  It certainly never would in a Salisbury.  Their biggest design deficiency is not having a thrust bearing for use in reverse.  Only a problem is you drive around in reverse all the time...  The number of worm gears is not an issue as the 3 pairs are bigger than the 6 pairs....   For new, the Ashcroft is the best choice.  I have a True-Trac.  I've always been able to find them used for very little money.

Good to know.  Probably not vastly different performance or reliability behind a stock Tdi, then.  A tuned V8 or TD5 might find any weaknesses, but I guess I don't need to worry about that...

[Peaklander]

9 hours ago, Snagger said:

 

I've been reading around, because I quite fancy them, and there seem to be three brands available for LRs.  Quaife, Eaton and Ashcroft.  The Quaifes appear best, even Ashcroft stating so, but are very costly.  Eaton are second dearest, but appear lower quality than Ashcroft, especially now they're built int he far east, with quite a few stories about spectacular failures. 

Just an aside I see you have suggested problems due to "far east". I know nothing about these Eaton units but I do know about Eaton generally, as I worked for them and ran an operation. They are such a high performing company placing huge demands on their design and manufacturing operations that they would never compromise their product because of geographical location.

I have also led manufacturing operations improvement work in other businesses in China and again there are some world class operations there. It's easy to tar them all with the same brush but I think you need to be cautious. 

[Snagger]

11 hours ago, Peaklander said:

Just an aside I see you have suggested problems due to "far east". I know nothing about these Eaton units but I do know about Eaton generally, as I worked for them and ran an operation. They are such a high performing company placing huge demands on their design and manufacturing operations that they would never compromise their product because of geographical location.

I have also led manufacturing operations improvement work in other businesses in China and again there are some world class operations there. It's easy to tar them all with the same brush but I think you need to be cautious. 

There is a range of quality from the region (Japan excepted, which seems to all be decent quality).  From what I have seen on my frequent visits, there is a lot more poor quality stuff than good.  That doesn't mean that a company having stuff manufactured overseas is going for lower quality, but quality testing of metalurgy is difficult, and I have come across a fair few comments about Eaton's reduction in quality purely due to this.  I have no first hand experience, but there are plenty of reports and reviews out there that explicitly state this.  But, of course, the internet is also less than reliable, and your personal experience does count for more that some random person's unverifiable claim.  I it had been just one claim, I'd ignore it, but several suppliers say the same thing, hence the concern.

[Peaklander]

Well just to close my aside, Eaton manufactures major systems for commercial aircraft and I bet you wouldn't make the same statements (without the first hand experience that you agree you don't have), on a forum discussing the very aeroplanes that you pilot. Hope you take that in the friendly way in which it is intended.

[Snagger]

Unfortunately, a lot of aviation engineering is not what it should be, and I see glaring design flaws that are never addressed, including  some which have caused fatal accidents and are continued by the manufacturer as a modification would be seen as an admission of liability for the accident.  Typically they pass the buck, blaming us, the line engineers, environmental conditions or planetary alignments; anything but admitting their own flaws.

But just because a company also works in aerospace, it doesn't mean that their other areas are done to the same standards.  GKN is a good example - no way are their car brake components, as decent as they are, of similar quality to aircraft brakes.  So that is not a good argument.

Don't take that as criticism of the Eaton staff.  That is not the intention, and as a former Ryanair employee, I'm all too keen to point out that a company with bad service isn't necessarily made up of bad employees!  I have, hover, come across numerous comments about a drop in quality, most seemingly US customers.  The same is true of many JLR parts, now made in China or India.  That doesn't make JLR a bad company, but we can't deny a drop in some parts' quality.  In Eaton's case, the issue is probably only a concern if you're doing very hard driving and perhaps wouldn't ever cause trouble for many of us.

[Ex Member]

Keeping in mind that these differentials are not really an Eaton product.  Eaton bought the company ten years ago.  There are always exceptions, but in my experience, company takeovers never results in an improvement is component quality.  Step 1 is to always cut costs at every corner and this causes the good employees to get Mildly miffed off and quit.  They get replaced by corporate monkeys.

Anyway, if you are buying new, get the Ashcroft ATB.  It is better designed and built.

[Snagger]

I wish Dave did a Salisbury ATB - I'd have one of those in a heartbeat..  I'm stuck with a choice between Quaife and Eaton, and there is not a shadow of a doubt which is better, but the price difference is marked, and that makes the choice difficult.  I'm not going to be rock crawling, so will the issues some of those customers had affect me?  Unlikely, but you never know...