Changing from 4 speed to 5 speed gearbox on LC 100

[Naveed]

Hi,
I am new to this blog and need some advice regarding changing the gearbox on my LC 100, 2000 Model. It originally has a 4 speed gearbox as you all know. I am considering changing the gearbox to the 5 speed one that came fitted on LC 100, 2003 to 2005 model. The purpose/idea is to have lower RPM on highway driving resulting in lower noise and higher fuel efficiency. My questions on the issue, if someone could guide me, are:
1. Does the 5 speed gearbox fit on the original 2000 model engine housing as such or does some alteration need to be made?
2. Do I need to change the differentials with the change of gearbox?
3. Do I need to change the 4×4 gearbox too?
4. What about the Electronic Command System (ECS)/computer? Would the new, 5 speed gearbox, need its own command system/computer control or would the old one work?
5. If a new ECS/computer is needed to be installed, that comes with the 5 speed gearbox, would it work fine with the old engine?

 

[Steve Wright]

I have never done it but to be honest I would not bother as first the final is poss the same for the four and the five speed box, you would be better looking for a 2004 5 speed model

 

[uHu]

The Engine ECU and transmission ECU are very different on the two. Your version has two separate ECUs, while the 5 speed has a combined Engine and ECT ECU. The signalling is different, and the cable loom. Even the signals to the instruments module (gauges and meters) are different. The new ECU controls the engine slightly differently as well. The changes that came together with the new gearbox and ECU, include a few small changes to the engine.

I have run the older type engine in a car with the new ECU and loom for 2 weeks, and that worked fine. The ECU didn't object to the missing solenoids and the "wrong" injection pump, but I don't think it could be a permanent solution without some modifications.
The ECU controls all the solenoids in the gearbox, and they are different on the two.

 

[Naveed]

Thanks for the responses. Very helpful indeed.
Regards.