ADD with a gear driven transfer case

[myunclesredtruck]

5th gear went walkabout in my uncles LN107, so I found a replacement G52 gearbox, realised that the transfer cases were different but put it in anyway. I sourced a gearbox mount to fit it as the gear driven t/case has a much wider flatter mount than for the chain driven t/case. Everything else lined up except for the front half of the rear tail shaft.

It's a bit too long and that puts the centre bearing bracket out of alignment.

The real kicker is that the LN107's selection of 4wd was electronic. Changing to the gear driven t/case meant the loss of the l4 sensor and the 4wd shift motor. Between some diagrams I found on here and a gregorys repair manual I've by-passed the 4wd ECU by jumping the switched earth to the ADD relay so that it now connects to the 4wd detection switch on the new gearbox.

Is this going to work? My uncle is going up to Fraser in about 3 weeks so I need to get this up and running in a robust way.

Thanks,
Chris