As you all may recall, I'm putting an LBZ in my 83 GMC truck. The donor truck is 06 2wd but the 83 will be 4wd. I'm racking my brain on all the ways I can get from A (2wd donor) to B (4wd 83) with this thing and I really REALLY want to be able to use an NP261 manual shift transfer case instead of a divorced NP205. Where I'm having trouble is converting the electronics on the donor to full 4wd so that the TCM, ECM and transfer case all work properly when engaged. So I think I might have an idea to not have to switch the electronics but I need to know if it's feasible/doable or if I need to go back to the drawing board on it....
On the 4wd allison, the speed sensor is on the back of the transfer case whereas it's on the allison tail housing on the 2wd, right?? What I'm thinking about is swapping the 2wd tail housing and output shaft for those for a 4wd transmission so that the NP261 will bolt up like it normally would for a 4wd application. The difference is, I'm thinking of drilling and tapping the 4wd tail housing so I can keep the speed sensor on the output shaft of the transmission yet have a bolted on NP261 like a 4wd. In this configuration, as far as the electronics are concerned, it should all stay and function as a 2wd but the truck will physically be able to engage in 4wd and the electronics not really "know" it.
1) is there room inside the 4wd tailhousing to put the exciter ring on the 4wd output shaft and mount the speed sensor?
2) Am I correct in thinking that the allison will still work just like any other 2wd allison and DMAX combo even when I pull the transfer case into 4wd?? It shouldn't "know" that it's got a transfer case behind it, right??? I don't see how this would be any different, as far as the allison is concerned, than swapping the differential gears to something else and that doesn't have any adverse, or incorrectable, effects as far as I know.
I think I've found some info on this on pirate4x4 where a guy bolted an NP205 to his allison and did just what I mention doing - tapping the 4wd tail housing and putting the speed sensor there. Difference is, he used an adaptor to mate the allison output shaft to the NP205 input shaft and that's where he was able to put the exciter ring. Could I possibly do something similar with the input snout/hub (not sure what it's called but I'm trying to say the piece that the allison output shaft goes into) of the transfer case by putting the exciter ring on it??? Looks like space is not gonna be a concern.
Allison to NP205
On the 4wd allison, the speed sensor is on the back of the transfer case whereas it's on the allison tail housing on the 2wd, right?? What I'm thinking about is swapping the 2wd tail housing and output shaft for those for a 4wd transmission so that the NP261 will bolt up like it normally would for a 4wd application. The difference is, I'm thinking of drilling and tapping the 4wd tail housing so I can keep the speed sensor on the output shaft of the transmission yet have a bolted on NP261 like a 4wd. In this configuration, as far as the electronics are concerned, it should all stay and function as a 2wd but the truck will physically be able to engage in 4wd and the electronics not really "know" it.
1) is there room inside the 4wd tailhousing to put the exciter ring on the 4wd output shaft and mount the speed sensor?
2) Am I correct in thinking that the allison will still work just like any other 2wd allison and DMAX combo even when I pull the transfer case into 4wd?? It shouldn't "know" that it's got a transfer case behind it, right??? I don't see how this would be any different, as far as the allison is concerned, than swapping the differential gears to something else and that doesn't have any adverse, or incorrectable, effects as far as I know.
I think I've found some info on this on pirate4x4 where a guy bolted an NP205 to his allison and did just what I mention doing - tapping the 4wd tail housing and putting the speed sensor there. Difference is, he used an adaptor to mate the allison output shaft to the NP205 input shaft and that's where he was able to put the exciter ring. Could I possibly do something similar with the input snout/hub (not sure what it's called but I'm trying to say the piece that the allison output shaft goes into) of the transfer case by putting the exciter ring on it??? Looks like space is not gonna be a concern.
Allison to NP205
makes sense though. 
