Thread: what gear box gives us a LT 230 transfer case

Originally Posted by JohnF

I do understand, if my understanding is correct from reading other Isuzuthreads, that the Transfer box to put behind a Isuzu is the LT230.

Now at home I do have a spare:--

1. LT77 gear box from a 1985 RRC-- the one advertised as being wrecked in the markets.
2. A R380 gear box from a 1995 Disco, the one advertised as being wrecked.
3. A ZF 4 speed Auto box from a dropped timing chain 1990 RRC.

So which of these has the LT230 transfer box that can sit behind a Isuzu 4BD1T and the MSA gearbox. Assuming we want Grubb's cheapest adaptor kit.

I'd say number 2 would be best option....

All of your options will be bolted to an LT230 (EDIT: The RRC w/ZF in your list may have a viscous t-case, which you don't want.). However you need to check the condition of the LT230 and the ratio.

As far as ratio goes, you want one fitted to a Hi-comp RRC box (1.003:1), TF727 (3-speed auto) box (1.003:1), or a disco (1.22:1 or a 1.21:1 Q-case).


Most SH LT230s will have the intermediate shaft hole flogged out from people not tightening the nut to preload the bearings. MR Auto can fix that for you if you give them the case and $100.

The ZF did not have a diff lock if I remember correctly, which I guess means that it does have the viscous coupling. So that is now out of my list.

How do I find out what these ratios are??

Is a later LT230 better than the earlier LT230, assuming the same ratios??

Originally Posted by JohnF

The ZF did not have a diff lock if I remember correctly, which I guess means that it does have the viscous coupling. So that is now out of my list.

How do I find out what these ratios are??

Is a later LT230 better than the earlier LT230, assuming the same ratios??

yes

Originally Posted by JohnF

The ZF did not have a diff lock if I remember correctly, which I guess means that it does have the viscous coupling. So that is now out of my list.

How do I find out what these ratios are??

Is a later LT230 better than the earlier LT230, assuming the same ratios??

Plugging the T-case serial number into the ashcroft website is the best way to ID it.

Some early t-cases did not have taper roller bearings (I have never seen one). Those with taper roller bearings are designated an LT230T.

In general later t-cases will be newer and more desirable. However if you want a 1.003, then this will have to be an earlier case from a rangie or 3.9D county.

If you use a disco or RRC case you will need to use the speedo drive from a 110. A disco (or RRC?) case will also mean that low and high are swapped - as the linkage is reversed, but this is not a problem.

The last of the D1s and the D2s got the "Q" case (LT230Q). These still have tapered intermediate bearings, however have smaller gear teeth to make them quieter (Q=quiet). Bush65 rightly says that the smaller teeth should make them weaker cases, but there is no evidence of this making a practical difference.

Originally Posted by isuzurover

Some early t-cases did not have taper roller bearings (I have never seen one). Those with taper roller bearings are designated an LT230T.

In general later t-cases will be newer and more desirable. However if you want a 1.003, then this will have to be an earlier case from a rangie or 3.9D county.

Mine ticks both those boxes. I have the 1.003:1 LT230R from a 1983 rangie which had the 3 speed TF727 auto.
People speak of the taper roller box being better, but TBH I have no idea what the problem is with the R.
It's been in about 6 years and 35,000km according to my records. Only problem has been leaks. Dodgy new seals that for some strange reason didn't seal against the output shafts.

Originally Posted by JohnF

I do understand, if my understanding is correct from reading other Isuzuthreads, that the Transfer box to put behind a Isuzu is the LT230.

Now at home I do have a spare:--

1. LT77 gear box from a 1985 RRC-- the one advertised as being wrecked in the markets.
2. A R380 gear box from a 1995 Disco, the one advertised as being wrecked.
3. A ZF 4 speed Auto box from a dropped timing chain 1990 RRC.

So which of these has the LT230 transfer box that can sit behind a Isuzu 4BD1T and the MSA gearbox. Assuming we want Grubb's cheapest adaptor kit.

please phone Darryl iwish to buy shifter for isuzu gearbox.

please quote the grubb 1091365 I wish to purchase shifter