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Sorry to bring up a frequently covered topic but I would like some advice.

I've wanted to fit higher ratio diffs on my 109 for some years now. I've recently acquired a 110 sailsbury axle. Now, I'm faced with one of two options.

#1 Gut the diff from the 110 and fit into the series casing. (Requires a special jig to stretch the casing) no problem, I could probably make one.

#2 convert the 110 axle to leaf. Easy enough.

The issue with #2 is that the axle measures some 160mm wider then the series axle (much more then I expected) meaning that I would need some gigantic spacers on the front axle.. not very safe or practical.  Alternatively I could convert a front defender axle to leaf which I have heard is not such a straight forward job either.

It's looking like the easiest solution would #1, though I've heard the task of removing the diff from a sailsbury can be tricky.

Would like to hear your thoughts 

Edited by youngengineer

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Easiest is to find yourself a Rover axle.

However, weight wise you could have issues.

Not sure how in the UK these days axles swops are regarded..

Bon Courage !

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54 minutes ago, Arjan said:

Easiest is to find yourself a Rover axle.

However, weight wise you could have issues.

Not sure how in the UK these days axles swops are regarded..

Bon Courage !

Easiest it not necessarily what I'm after. But I do take your point on the legality side of things. It is recorded as historic and already has a 200tdi fitted which is declared. Axles might be a step too far. Maybe I will attempt to swap the diffs instead.

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The diffs aren't hard to swap. Getting the mesh correct is harder as swapping shims isn't a two minute job. Also, experience from a few members suggests it's not a pleasant drive after conversion and tends to tip the series box over the edge with the extra resistance. An overdrive is a far better option IMHO. 

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Thanks for the input. Yes I did hear that the extra strain on the series box was an issue with the higher ratio diffs.  I should probably mention that I also have an lt77 (almost) fitted. The meshing is something I've heard about but not looked into.

 

The other option is to stick with the series diffs and fit an Ashcroft high ratio lt230 gearset.

Edited by youngengineer

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I thought there was some shenanigans between metric & imperial Salisbury diffs/bearings... from the mists of time when Moglite converted his Ibex to Salisburys.

TBH everyone I've heard talk about rebuilding a Salisbury says getting the diff in/out isn't that hard, the "stretch" is very minimal, ISTR moglite just used a pair of pry-bars.

If you're running an LT230 then upping the ratio is easy and means you keep a very low low-ratio, there's 1.003:1 LT230's from older Range Rovers out there if you don't want to pay £££ for a set of gears from Ashcroft.

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58 minutes ago, FridgeFreezer said:

I thought there was some shenanigans between metric & imperial Salisbury diffs/bearings... from the mists of time when Moglite converted his Ibex to Salisburys.

TBH everyone I've heard talk about rebuilding a Salisbury says getting the diff in/out isn't that hard, the "stretch" is very minimal, ISTR moglite just used a pair of pry-bars.

If you're running an LT230 then upping the ratio is easy and means you keep a very low low-ratio, there's 1.003:1 LT230's from older Range Rovers out there if you don't want to pay £££ for a set of gears from Ashcroft.

 

 

 

 

I did hear something about the metric/imp diff issue, was some time ago now though and I can't remember where I read it. Either way its looking more likely that I will stay with series diffs and fit a 1.003 transferbox as Ashcroft speed calculator gives me 70mph at sub 3000rpm on series diffs which is in the range I'm aiming for.

 

As you mentioned, finding a used 1.003 TB will be far more economical. Ashcroft looks ok at £220 but once you add the VAT and the "additional" gears it's getting into the £400 range! Starting to get expensive..

Issue is finding a transferbox from a 3 speed auto range rover. 

 

Edited by youngengineer

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Don’t do it.  I am one of several on here that did, and it was dire.  It uses more fuel, because you’ll spend a lot more time in lower gears, and the car will accelerate like a sloth.  It’s just too high a gearing step, at about 35% increase.

If you fit just the 3.54 diffs by themselves, you probably won’t cause a gear box failure if you drive sensibly, but if you also fit an overdrive or High Ratio Transfer Case (Ashcroft), then it’s just a matter of time until you strip the teeth off third gear.  I did that, then another member did a few years later in a textbook copy of the failure.  

Many of us will vouch for how horrible the car will be to drive, even without the overdrive or HRTC.  But, if you are compelled to learn by your own mistakes, rather than those of others, then it’s an easy swap on the front end if you get the diff from a 200Tdi or earlier RRC, Discovery or Defender, and the rear can be swapped from axle to axle without undue trouble.  In theory, setting up a Salisbury is meant to be time consuming, but the reality of a diff swap with used parts is very easy as the tolerances of the casings is pretty good and the existing shims are almost always right - leave the existing pinion bearing shims in place and reuse the existing collapsible spacer (you don’t even need to remove the pinion seal), and just fit the 3.54 pinion using the existing bearings.  Then fit the 3.54 diff carrier, complete with its own bearings and shims unmolested, and it should work right off the bat.  Sounds like a bodge, but the tolerances really are good enough to allow this.  Do the pinion nut up to about 150’lbs and you’re done.

Fitting the later axles is easy at the back end, not so much at the front, where the steering becomes an impediment and you may also run into front UJ clearance if you have a Defender version of the Tdi (low slung fuel pump and low engine mount underneath it).  You can look up the details of how I did that on my blog (axles section) - club the signature below.

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2 hours ago, Snagger said:

Don’t do it.  I am one of several on here that did, and it was dire.  It uses more fuel, because you’ll spend a lot more time in lower gears, and the car will accelerate like a sloth.  It’s just too high a gearing step, at about 35% increase.

To be fair, I did it in mine and the only problem was low range wasn't as low as I'd like - but that was behind a 3.9 V8 and even with 3.54 diffs & overdrive it wanted higher gearing on the motorway.

However, a 5-speed box and LT230 is by far the nicer option these days unless the truck is a properly original Series. If it's already had an engine swap then crack on.

All I've heard about sticking with Series box & using the HRTC or LT230 adapter is that it's expensive and uncivilised and your main box is still weak.

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9 hours ago, youngengineer said:

finding a used 1.003 TB will be far more economic

I found that finding one was not easy... and ended up stumping up for the Ashcroft kit. You may have better luck, especially if you can wait for one to appear. 

 

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8 hours ago, Snagger said:

Don’t do it.  I am one of several on here that did, and it was dire.  It uses more fuel, because you’ll spend a lot more time in lower gears, and the car will accelerate like a sloth.  It’s just too high a gearing step, at about 35% increase.

If you fit just the 3.54 diffs by themselves, you probably won’t cause a gear box failure if you drive sensibly, but if you also fit an overdrive or High Ratio Transfer Case (Ashcroft), then it’s just a matter of time until you strip the teeth off third gear.  I did that, then another member did a few years later in a textbook copy of the failure.  

Many of us will vouch for how horrible the car will be to drive, even without the overdrive or HRTC.  But, if you are compelled to learn by your own mistakes, rather than those of others, then it’s an easy swap on the front end if you get the diff from a 200Tdi or earlier RRC, Discovery or Defender, and the rear can be swapped from axle to axle without undue trouble.  In theory, setting up a Salisbury is meant to be time consuming, but the reality of a diff swap with used parts is very easy as the tolerances of the casings is pretty good and the existing shims are almost always right - leave the existing pinion bearing shims in place and reuse the existing collapsible spacer (you don’t even need to remove the pinion seal), and just fit the 3.54 pinion using the existing bearings.  Then fit the 3.54 diff carrier, complete with its own bearings and shims unmolested, and it should work right off the bat.  Sounds like a bodge, but the tolerances really are good enough to allow this.  Do the pinion nut up to about 150’lbs and you’re done.

Fitting the later axles is easy at the back end, not so much at the front, where the steering becomes an impediment and you may also run into front UJ clearance if you have a Defender version of the Tdi (low slung fuel pump and low engine mount underneath it).  You can look up the details of how I did that on my blog (axles section) - club the signature below.

Thanks for that very detailed write up. That's pretty much all the information I needed. 

I think I will finally go for the cheapest option which uses parts which I already have avoiding any need to go through Ashcroft.

That is, TDI defender 110 gearbox (lt77) and transfercase (lt230) (I believe 1.4 ratio) and 3.54 diffs. That should give me the exact same gearing as a 110 defender which unfortunately is a tad low but still sub 3000rpm at 70mph.

In the future I could always drop a 90 transferbox in with 1.2 ratio which would still be quite a bit cheaper then an Ashcroft kit.

Now before I tackle the sailsbury tomorrow. Do we know if there is any truth to the what fridge mentioned about the imperial/metric sailsbury incompatibility?

Edited by youngengineer

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8 hours ago, youngengineer said:

a 90 transferbox in with 1.2 ratio

You'll be wanting a Discovery LT230 for a 1.2 ratio. All Defender / 90 / 110 were 1.4, with the exception of the NA (Naturally exAsperated) Diesel engine 110's which were 1.6.

Of course, you might find one out a 90 that used to be in a Disco :P

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I believe that all Salisbury diffs are Imperial, given their Dana roots, but stand to be corrected on that.  I didn’t come across any differences using an earlier 110 (pre Defender) axle and diff.

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17 hours ago, FridgeFreezer said:

To be fair, I did it in mine and the only problem was low range wasn't as low as I'd like - but that was behind a 3.9 V8 and even with 3.54 diffs & overdrive it wanted higher gearing on the motorway.

However, a 5-speed box and LT230 is by far the nicer option these days unless the truck is a properly original Series. If it's already had an engine swap then crack on.

All I've heard about sticking with Series box & using the HRTC or LT230 adapter is that it's expensive and uncivilised and your main box is still weak.

Series box is 1.15:1, so unless you use a V8 high ratio unit, you’d be lowering the ratios with an LT230, even from a Discovery or RRC.  You could add the 3.54 diffs with an LT230, and some combinations may work out, but as you said, the weak spot is in the gear box, not transfer box.

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2 hours ago, daveturnbull said:

You'll be wanting a Discovery LT230 for a 1.2 ratio. All Defender / 90 / 110 were 1.4, with the exception of the NA (Naturally exAsperated) Diesel engine 110's which were 1.6.

Of course, you might find one out a 90 that used to be in a Disco :P

Later TD5 and TDCI 90s are 1.2, I believe.

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44 minutes ago, Bowie69 said:

Later TD5 and TDCI 90s are 1.2, I believe.

I was about to say the TDCi ones are, 110 too I believe. But not heard of a factory 1.2 Td5 defender.

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1 hour ago, Snagger said:

Series box is 1.15:1, so unless you use a V8 high ratio unit, you’d be lowering the ratios with an LT230, even from a Discovery or RRC.  You could add the 3.54 diffs with an LT230, and some combinations may work out, but as you said, the weak spot is in the gear box, not transfer box.

I am lowering the ratio of the TB but the LT77's 5th is overdrive so it's working out lightly better then a series box but with better gear spacing.

Edited by youngengineer

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4 hours ago, daveturnbull said:

You'll be wanting a Discovery LT230 for a 1.2 ratio. All Defender / 90 / 110 were 1.4, with the exception of the NA (Naturally exAsperated) Diesel engine 110's which were 1.6.

Of course, you might find one out a 90 that used to be in a Disco :P

Good to know. Plenty of discovery lt230s on eBay. Might be worth a punt. Not sure where I heard about that the 90 had a lower ratio 

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5 minutes ago, youngengineer said:

Good to know. Plenty of discovery lt230s on eBay. Might be worth a punt. Not sure where I heard about that the 90 had a lower ratio 

Careful on the wording.... 1.4 is a lower ratio than a 1.2.

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Just to spice it up I thought there were a few (possibly V8's) with 1.192:1 and the later D2's with the Q gears were 1.211:1 for some reason.

Maybe I've just been lucky finding 1.003:1 boxes, they're rarer (like 1.6's) but I haven't found them unobtainable.

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1.003:1 boxes will be harder to find now, as it’s the box the Cummins boys love. At the very least they’ll get Cummins tax added to the price. 

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Careful if you buy a disco LT230; some of the disco 2's didn't have a difflock either because the external mechanism isn't there, or on some it isn't there inside either. You probably wouldn't want the latter.

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3 minutes ago, cackshifter said:

Careful if you buy a disco LT230; some of the disco 2's didn't have a difflock either because the external mechanism isn't there, or on some it isn't there inside either. You probably wouldn't want the latter.

D2s (I think all) don't have the speedo output on the rear housing either.

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Ok so I know that it's been mentioned how horrible the conversion would be but after a 30 mile trip stuck at 45mph being overtaken by lorries I decided enough was enough.

Usually my stubbornness comes back to punish me with a vengeance but on this occasion I am extremely pleased with my decision.

I decided to swap the diffs rather then axles. The process was simple enough, the tool was made in under 10 minutes from angle iron and M12 threaded rod 

No longer do i need 4th gear in city traffic. I can happily use 1 to 3rd upto 40mph. Still pulls like a train, no "bogging down" what so ever. Actually very usable gearing now.

I followed snaggers guide which was a great help. But I have to disagree on the outcome, I certainly would never go back to 4.7

Hmm, this makes me wonder tho snagger. Are you using the original series engine? I'm running a lightly modified 200tdi, hybrid turbo (1.4bar boost) 200tdi intercooler, modified fuel pump and that's all. 

Feels very happy with the 3.54 diff.

IMG_20191210_154021.jpg

IMG_20191210_155843.jpg

IMG_20191210_160543.jpg

Edited by youngengineer

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