Gearbox and Lt230 Transfer Q's - 4BD1-T

[110Landy86]

1)

Can anyone advise what the difference is (specifically related to the gearig) between discovery lt230 and that fitted to the lt85 behind the Isuzu/ v8.

2)

My lt85 recently carked it in spectacular fashion whilst attempting to roll start; this being my second gearbox failure in 430K km. I now find myself at a crossroad with the following fitment options behind a 4bd1-t:

A) Reco lt85 solid case/ lt230
B) Reco lt85 solid case/ lt230 with tapered roller bearings
C) Lt95
D) Isuzu box (various)
E) R380 suffix L

With the major pros/ cons briefly summarised as follows:

A) weak box - apparently
B) reasonably strong though still prone to end float and 5th gear wear
C) very strong box - 4 speed though (major downside) - new clutch - b/ housing (have access to right one) - hi-lo gear lever relocation - vacuum operated d/lock (ok)
D) strong, well matched to engine - modification works - extended downtime - costly
E) mod works required.

As you can appreciate I'm having difficulty in deciding which way I should go. I like having a 5th gear but don't want to outlay big $$$ repeating this job anytime soon.

Any advice?? Experiences?? etc to help my decision process progress is appreciated!!

Cheers JP

[Bearman]

Option C with a TRB 0.996 ratio. You will hardly notice the difference. Also you don't change gear much at all, 4th is good from 40 - 140K :D. You can use the LT85 5 speed transmission tunnel with a LT95 - minor mod required to locate the transfer lever into LT230 position, same as the Perenties have fitted to them.

[Vern]

D. With the right kit it bolts straight in, should take no longer than bolting in an lt85, once you have all the bits that is. Mine bolted together in no time, and was very straight forward to install.:)

[Judo]

I'm expecting this day will come for me too. I have an LT85+LT230 and history is unknown to me. Vehicle has done 270k with a turbo for quite a number of them.

Have you looked at prices on the Ashcroft site? I suspect they are what will determine my decision.

From what I've read the Isuzu box is the best, but the most effort as well.
IMO the R380 is nice compared to the LT85 and if prices are OK, I would go an R380 over LT85. But also more effort.
LT85 on strength is apparently similar to an R380. The benefit is, a straight swap for reco box.

LT95 is a good choice if you are happy with 4 speed AND you can find all the parts. I hear all the required parts for a conversion are getting hard to come by.

So my currently thinking is either a reco LT85, or an R380. That's my 2c from reading on the forums. :)

[Judo]

^ lol First 3 posts are 3 different answers. :D

[Vern]

Justin, personally I think it is no more effort to install the Isuzu box if you are to use the grubbs kit. I think I may have spent half an hour playing with the shifter to bring the gates closer together, other than that it is a straight forward gearbox install.:)

[Vern]

For me, its options D, then C, then who cares:D

[isuzurover]

Option D. No question.

However my LT85 is still going strong (touch wood), and on its 3rd LT230!

A Disco 1 LT230 would be 1.222 LT230T or 1.211 LT230Q. Disco 2 1.211 LT230Q.

I find the disco case a good ratio, but with an isuzu box the original 1.003 ratio would probably be better.

[Judo]

Justin, personally I think it is no more effort to install the Isuzu box if you are to use the grubbs kit. I think I may have spent half an hour playing with the shifter to bring the gates closer together, other than that it is a straight forward gearbox install.:)
I didn't realise it could be that easy. I need to look into this kit more.

[Vern]

Well if your ever down this way you can look at mine installed in the car. Fits well.:)

[steveG]

Well if your ever down this way you can look at mine installed in the car. Fits well.:)

Looked at it........
Just hurry up and get it running so I can have a drive :)

Steve

[110Landy86]

Thanks for the everyone's responses.

Ill have to get privy with Grubbs kit. is suited to all Isuzu boxes or type in particular? And is existing tunnel etc still ok to use?

[Vern]

Msa boxes I think.
And Steve, feel free to lend a hand:), I've run out of time this year to get it on the road, should have it going though.:(

[Vern]

Thanks for the everyone's responses.

Ill have to get privy with Grubbs kit. is suited to all Isuzu boxes or type in particular? And is existing tunnel etc still ok to use?

As you have the lt 85, you just need the msa box, his adapter, the Isuzu to land adapter ring and some clutch bits I think. You should be able to offload your lt85 and bell housing to recoup some funds.:)

[303gunner]

As you have the lt 85, you just need the msa box, his adapter, the Isuzu to land adapter ring and some clutch bits I think. You should be able to offload your lt85 and bell housing to recoup some funds.:)
I thought that the benefit of using the Isuzu gearbox with the Isuzu engine was that it's all Isuzu truck components, no rare Landie components required?

[Hall]

I have a Isuzu MSB box in my ute. Basically a MSA on its side as in the gear selection is from the side not the top. What I have found is it,to me at least, is a 4 spd box with a low first added. So not much in overdrive. This of course could be the LT230 transfer case ratio. Great stupidly low first but not a high fifth gear at all. Good strong box though and better than the lt95 that was in it. Up side of a marginal fifth gear is I can run 32" or 33' tyres no problem and that gets the revs down a bit in fifth.
Cheers Hall

[Vern]

I thought that the benefit of using the Isuzu gearbox with the Isuzu engine was that it's all Isuzu truck components, no rare Landie components required?

It is, but you also need an Isuzu truck flywheel, Isuzu truck starter motor, Isuzu truck flywheel and clutch. This is the way I went as I had both so opted for this option. As 110landy86 already has the rover parts, he may as well utilize what he has, unless he can find the truck bits at a good price and can offload his land conversion.

[flagg]

People talk about Grubbs kits like they are available. :(:angel:

I converted my knackered LT85 to an R380 (at great expense) prior to Grubb doing his kits. I really like the R380 though - it is a nice tight, smooth box that is enjoyable to drive. It really changed the feel of the 110 for the better and the later ones are quite strong with many people using them behind 4bd1Ts for a LOT of kms.

That said, if I were to do it again (and grubb was going to do a run of his kits) I would use a grubb kit.. but I've not driven one to judge the feel of them.

[110Landy86]

Hey guys,

1) I have a rear diff from a 1987 v8 110 which I plan to reco and fit to my 1987 isuzu 110 as my existing diff is said to be super costly to repair (crown n pinion cactus). Question; Will I be able to successfully fit the v8 diff or will the ratio conflict with my existing front diff (ratio)??

2) Also, I have a lt85 with disco type lt230 t/c. Will the ratio be higher or lower than the original/ stock arrangement? I understand that the disco t/c has a taller ratio is this correct? Any first hand experiences with this setup?

Cheers JP

[justinc]

all rangies, defenders, and counties run 3.54 ratio diffs. the disco lt230 is 1.222:1 ratio, the original county v8 one will be 1.41:1.

jc

[110Landy86]

Sorry I should clarify. the existing/ stock gearbox is factory fitted to the Isuzu .

[justinc]

in that case it will be 1.222:1 or 1.003:1. most were the 1.003 but mine was 1.2:1. i converted to lt95 when i fitted the 4bd1 to my rrc, i have also seen a factory fitted 1.2 ratio lt230 to a 4bd1 120" 1991 model.


jc

[110Landy86]

Hey Justin when you say 1.222:1 is that 1.222 rev of the output shaft to 1 rev the input or vice versa?

I plan to increase my t/c gear ratio as atm I'm sitting at about 2800/2900 at 100km/hr which is ridiculously high, given the original was about 2300/2400 at similiar speed.

Basically is it a 1.4:1 or 1.003/0.996:1 ratio that would produce a higher ratio? (Without changing tyre sizes- running original 16R).

Also, are you or others aware of aftermarket higher gear ratios??

Cheers JP

[slug_burner]

Hey Justin when you say 1.222:1 is that 1.222 rev of the output shaft to 1 rev the input or vice versa?

I plan to increase my t/c gear ratio as atm I'm sitting at about 2800/2900 at 100km/hr which is ridiculously high, given the original was about 2300/2400 at similiar speed.

Basically is it a 1.4:1 or 1.003/0.996:1 ratio that would produce a higher ratio? (Without changing tyre sizes- running original 16R).

Also, are you or others aware of aftermarket higher gear ratios??

Cheers JP

That is 1.222 turns of the input shaft for 1 turn of the output shaft. If you want to drop your engine revs for the same road speed then you will have to go to the 1.003 or the .996.

If you look through the 4BD1 T threads you will get opinions as to what ratio is best. Look through Justin Cooper's Isuzu related threads and I am sure he has spoken about it.