A couple or three questions....

[Bowie69]

The lt77 takes an lt230 transfer case, which is the bit you convert to 2wd.

 

[Bigj66]

19 minutes ago, Bowie69 said:

The lt77 takes an lt230 transfer case, which is the bit you convert to 2wd.

 

So just doing the centre diff mod to the LT230 will give selectable 2/4WD?

https://www.ashcroft-transmissions.co.uk/miscellaneous/part-time-4wd-kits/90/110-lt230-part-time-kit.html

[Bowie69]

Yes.

[FridgeFreezer]

^ What Bowie said, there's even a full thread on it with pictures by yours truly in the technical archive.

[Bigj66]

Good write up👍
 

What would be the best ratio with for instance a 4.6 V8 and either the 4:7 or 3:5 diffs? Focus mainly on road driving and motorways but with the hills of Wales to deal with too?

Is this a similar kit by Syncrogearboxes? No useless FWH...

https://www.onlinegearboxparts.com/product/lt230-differential-spool/

[Bowie69]

What size tyres are you going to run?

[Bigj66]

Probably a 7.50 or 235

By the way, remember that thread about the 6 cylinder SWB I had going that migrated into the SWB V8 auto discussion.....?

Circumstances have now changed so I’m back there again but I’ll start a proper build thread for this and explain the background.

The conversion of the 110 to V8 is now shelved as that will be sold as is but the info gained will find its way into the Series build.

[Bowie69]

With a 4.6 V8, 4.7 diffs, and 32" tyres you could probably use a 1:1 transfer box, and end up with a lovely lazy cruise, as well as a really low low range.

If it's more hilly where you are, maybe go with a more common 1.2. 

If you run 3.54s, then the considerations are similar, but choose between 1.2 and 1.4. your low range won't be quite so low, though.

 

[Bigj66]

1 minute ago, Bowie69 said:

With a 4.6 V8, 4.7 diffs, and 32" tyres you could probably use a 1:1 transfer box, and end up with a lovely lazy cruise, as well as a really low low range.

If it's more hilly where you are, maybe go with a more common 1.2. 

If you run 3.54s, then the considerations are similar, but choose between 1.2 and 1.4. your low range won't be quite so low, though.

 

Is a Disco LT230 1.2 as standard and the Defender 1.4?

[FridgeFreezer]

2 hours ago, Bigj66 said:

What would be the best ratio with for instance a 4.6 V8 and either the 4:7 or 3:5 diffs? Focus mainly on road driving and motorways but with the hills of Wales to deal with too?

 

2 hours ago, Bigj66 said:

Probably a 7.50 or 235

Our ambulance runs that combo - 4.6 V8, R380, 1.4:1 LT230 with Roamerdrive, 3.54:1 diffs and 235/85R16 tyres and it works well, I suspect in a lighter truck (especially a SWB) you'd more happily use the 1.2 ratio LT230 as TBH most of the time you could leave the overdrive engaged in the ambulance and not notice - it's only big hills where the weight & aerodynamics make themselves known! Bear in mind that's a 2.8ton truck with the frontal area of a block of flats

With 4.7 diffs you might drop to 1:1 ratio in the LT230 but those are harder to find.

[Bigj66]

And if say I went with a 4.6 or possibly a 4.0 or 3.9 SERP engine then with the 1.2 LT230 and 3.54 diffs would I even need an overdrive as it should be the same power output and gearing as the original vehicles except for slightly taller tyres?

[Bowie69]

8 minutes ago, Bigj66 said:

Is a Disco LT230 1.2 as standard and the Defender 1.4?

Disco normally 1.2, Defender normally 1.4.

There's normally a sticker on the box, otherwise you can check the code against Ashcroft Transmissions list of serial numbers on their site.

Ashcroft are doing 1:1 ratio conversions to LT230s now:

https://www.ashcroft-transmissions.co.uk/lt230-ratio-changes/1-003-gear-set.html

Or 1:1.1 if you can't decide!

https://www.ashcroft-transmissions.co.uk/1-100-gear-set.html

Note, you need to make sure you have the right box to convert the ratios.... check with Ashcroft if you go that route.

[Bigj66]

8 minutes ago, Bowie69 said:

Disco normally 1.2, Defender normally 1.4.

There's normally a sticker on the box, otherwise you can check the code against Ashcroft Transmissions list of serial numbers on their site.

Ashcroft are doing 1:1 ratio conversions to LT230s now:

https://www.ashcroft-transmissions.co.uk/lt230-ratio-changes/1-003-gear-set.html

Or 1:1.1 if you can't decide!

https://www.ashcroft-transmissions.co.uk/1-100-gear-set.html

Note, you need to make sure you have the right box to convert the ratios.... check with Ashcroft if you go that route.

Ok cheers. I’ve been offered a Disco auto box with LT230 transfer box so that was why I was asking about the ‘standard’ ratios. I can get the guy to check the sticker though no worries.

[Bowie69]

It will be 1.2 unless someone swapped it out to put big tyres on it.

[Bigj66]

17 minutes ago, Bowie69 said:

It will be 1.2 unless someone swapped it out to put big tyres on it.

As far as I know it’s standard but he’s going to check for me.

So if it is then it can be used with 3.54 diffs and a V8 of 3.9 cc and above?

[FridgeFreezer]

1 hour ago, Bigj66 said:

As far as I know it’s standard but he’s going to check for me.

So if it is then it can be used with 3.54 diffs and a V8 of 3.9 cc and above?

Should be absolutely fine, won't need an overdrive. As Bowie says, you might get away with one of the 1.1 ratio boxes if you find one but 1.2 will be fine and they're ten a penny.

With our 1.4 transfer box + OD we cruise at 70mph at 2200rpm, with a 1.2 box and no OD you'll be at ~2400rpm, no big difference.

[Snagger]

4 hours ago, Bigj66 said:

And if say I went with a 4.6 or possibly a 4.0 or 3.9 SERP engine then with the 1.2 LT230 and 3.54 diffs would I even need an overdrive as it should be the same power output and gearing as the original vehicles except for slightly taller tyres?

You can only fit an overdrive to a 1.4 LT230.  But you would get good gearing ratios for that engine with the 1.2 and 3.54 diffs.

[Bigj66]

Looks like I have the auto box, LT230 1.2 and a pair of 3.54 diffs sorted.

If the auto box doesn’t work then I’ve just picked up a conversion kit for the Series box. Now I just need a decent SERP engine.

Will start a build thread for it👍

[Bigj66]

The diffs are off a 95 Disco so will the spline pattern match the Series half shafts?

[Bowie69]

24 spline at that age, I believe, so no.

Trying to remember what's the best way to sort that out, but my brain is drawing a blank....

[Bigj66]

6 minutes ago, Bowie69 said:

24 spline at that age, I believe, so no.

Trying to remember what's the best way to sort that out, but my brain is drawing a blank....

Early RRC diffs?

[Gazzar]

1 hour ago, Bigj66 said:

The diffs are off a 95 Disco so will the spline pattern match the Series half shafts?

Ashcroft do series half shafts that are 24 spline, at the back.

[Bowie69]

40 minutes ago, Bigj66 said:

Early RRC diffs?

Well yes, or any 90 diffs, but was trying to get you being able to use what you have.

As above, Ashcroft do rear 24 spline shafts, front is another matter.

[Bigj66]

Ok cheers all. Looks like I need to source some 10 spline diffs then.

[Bigj66]

On 3/16/2020 at 10:52 AM, Bowie69 said:

Disco normally 1.2, Defender normally 1.4.

There's normally a sticker on the box, otherwise you can check the code against Ashcroft Transmissions list of serial numbers on their site.

Ashcroft are doing 1:1 ratio conversions to LT230s now:

https://www.ashcroft-transmissions.co.uk/lt230-ratio-changes/1-003-gear-set.html

Or 1:1.1 if you can't decide!

https://www.ashcroft-transmissions.co.uk/1-100-gear-set.html

Note, you need to make sure you have the right box to convert the ratios.... check with Ashcroft if you go that route.

I might have a chat with Ashcrofts about the ratios. It might be easier to uprate the LT230 with the 2WD mod and the 1.1 gear ratio and keep my 4.7 diffs rather than change to 3.54 diffs.