AWD/4x4 EV Swap (leaf donor)

As I was searching for cool AWD vehicles I can across this leaf ev swapped Land Cruiser. 
 

He used mostly leaf parts for the build, the interesting thing to me is he didn't use a transmission at all, instead he mated the leaf motor up to the transfer case. 
 

He installed another "black box" gear box in front of the factory Land Cruiser transfer case .

My question is, what if you didn't have the extra black box gear box, and just ran the leaf motor directly to the stock transfer case? 
 

Would it only go 20mph? Would the electric motor "stall out" trying to go up a steep grade? 
 

I don't really understand enough to think though the advantage of adding the black box vs right to the factory transfer case. 

I'd guess it would "stall out" trying to go up a steep grade. An EV motor typically has 3-5x the rev range of an ICE. Typically they have a single gear ratio somewhere around 10:1. With the TC in a 1:1 high range and diffs in the 4:1 ballpark, that's not much gear reduction. With another 4:1 reduction that's around 16:1 which could make sense for lower speed usage with huge offroad tires.

In reply to GameboyRMH :

What does the 4:1 and 16:1 actually mean? 
 

Is it every 4 rpm of the motor the driveshafts go around once? Or tire revolution? 

Somebeach (Forum Supporter) said:

In reply to GameboyRMH :
 

Is it every 4 rpm of the motor the driveshafts go around once? Or tire revolution? 

Are those not the same?
I think that's what he means, overall axle ratio.

In reply to buzzboy :

I thought the ratio in the differential would change how many times the tire would go around per every revolution of the driveshaft? 

The Leaf has ~8:1 total gear reduction between the motor output and the tires, and the Leaf comes with ~25 inch tall tires.

If you put 33 inch tall tires on a Leaf, you'd want 10.6:1 total gear reduction simply to keep the same performance on pavement.

Typical ring&pinion ratios between 3:1 and 4:1 are not enough gear reduction to use the motor output directly (unless you are using 12" tall go-kart tires, or trying for a 200mph land speed record).

The 4:1 Black Box planetary might be slightly more reduction than "ideal", but the goal was off-road performance and 70mph top speed is still streetable.

At maximum current, the Leaf motor can produce around 200lb-ft of torque from 0-3k RPM.  Above 3k RPM the motor is limited by power output instead of torque.  'Redline' is 10k RPM.

Interesting build , 

In the comments he says he gets 30 mile range off road and double that on the street .