Thread: 4 speed to 5 speed gearbox swap

Originally Posted by The Mutt

I've spent hours (feels like days) going through postings about gearbox swaps, it's all starting to get a bla, bla, bla. So I don't get it wrong I thought I would ask a few questions.

As we already have a 4BD1 installed in our Rangie with the integrated 4 speed and transfer box, can I remove the gear box from the bell housing and bolt a Range Rover or Discovery 5 speed box straight on?

Is the LT230R or LT230T the best 5 speed to add behind the 4BD1.

Sick of trying to find 5 gear on a 4 speed box

Glenn

G'day Glen,
It's doable but personally I would stick with the LT95 4 speed as they are a stronger box than any of the 5 speed ones. You would need a T t/case with 1:1003 ratio to keep the revs down. There is much speculation as to which 5 speed is the best to use, either LT85 or R380. You will need a LT85 to Isuzu bellhousing for either of these as the Lt95 one won't fit the 5 speed boxes.

You will need a different bellhousing.

By discovery / rangie gearbox I presume you're talking about an R380 gearbox, as fitted to the rangie & disco post 94. LT77 gearboxes (pre 1994 discovery) will be chewed out by the 4BD1 in no time and not worth the effort.
LT85 5 speed gearboxes were fitted to 4BD1 110 counties from 1985 onwards. You'll need an LT85 bellhousing for either an LT85 or R380 (5 speed gearbox conversion). rare as a hens tooth I'm told.

The LT85 bellhousing will need modification to fit an R380 gearbox - do a search on 4BD1 R380 conversion, several members on here have done the conversion.

If you want a 5 speed box, have you thought about an overdrive, or perhaps one of the Isuzu MSA boxes with The Grubb's kit? Might be better alternatives.

The R380 and LT85 are 'toys', have been and WILL be lunched behind a torquey 4BD1t. The LT95 with a TR transfer case is the best landrover have to offer behind these engines IMO, As brian says use a 1.003:1 high range gears set and 32"/ 33" tyres or go with the MSA Isuzu box from The Grubb.
My LT95 with .996:1 high range and 33" tyres is about 2100RPM at 100km/h


EDIT: use this to help work it out; http://www.kabamus.com/garage/gears.html (PS: Just think how fast you could go if the 4BD1 could do 8000rpm )

JC

Conversion to 5 speed might stay on the Maybe list, I don't have a lot of time to muck aroud at the moment, if it was a straight bolt up .....

In the meantime I'll keep researching and look around for a suitable bellhousing , gearbox and transfer case.

NOTE: after a few calls I know we can get a factory LT85 5 speed with LT230 that had been on a 4BD1 for $1100, ready to bolt on after a rebuilt, already rebuilt for $3750, for approx $3500 we can get a R230 from an '94 to '99 Disco and a LT230Q already rebuilt from a series 2 Disco and bellhousing modification to bolt up to our 4BD1 .... will we / won't we?

Glenn

How much of a bolt up is Grubb's MSA conversion?

Originally Posted by The Mutt

Conversion to 5 speed might stay on the Maybe list, I don't have a lot of time to muck aroud at the moment, if it was a straight bolt up .....

In the meantime I'll keep researching and look around for a suitable bellhousing , gearbox and transfer case.

NOTE: after a few calls I know we can get a factory LT85 5 speed with LT230 that had been on a 4BD1 for $1100, ready to bolt on after a rebuilt, already rebuilt for $3750, for approx $3500 we can get a R230 from an '94 to '99 Disco and a LT230Q already rebuilt from a series 2 Disco and bellhousing modification to bolt up to our 4BD1 .... will we / won't we?

Glenn

Don't. Either of them.

JC

Originally Posted by Dougal

How much of a bolt up is Grubb's MSA conversion?

the whole thing is a bolt up, only fabbing is to the floor for gearshift location. I stuffed around with the shifter on mine a bit just to shorten the throw and shift between gates to get it to my liking, but that was dead easy, took about 20min. This conversion for your car Mutt would cost around the same as those you posted.

Let me come up to speed here keeping in mind we have a '88 Rangie with a 2in body lift.

The MSA is an Isuzu 5 speed is a short throw gear stick box (unlike the LT95) that bolts up directly with the 4BD1 installed in an '80s Land Rover.

The Conversion kit is for a LT230 to bolt up keeping the shift lever in the original location without he need to modify the drive shafts.

Do I keep the LT95 Clutch?

Do I keep the original starter motor and does the starter motor line up OK?

Other than the tunnel, what else needs modification?

Sick of hunting for 5 gear on a 4 speed box
Glenn