This is one of those aspects I've considered to be missing from the Phantom's array of modifications. I've considered quite a few options, which have ranged from installing Air Lockers, to changing the tubes, to other more radical thoughts. Basically, the inability to install diff locks arises from the 7:37 guchha which has been installed. Now, this guchha is what gives the Phantom such enormous low-gear torque and take-off despite such oversized wheels. However, it also inhibits our ability to install lockable differentials because of the incompatibility of ALL Toyota axles (Series 60, 70, and 80). The nearest compatible guchha which CAN be fitted in these axles is the 9:37 one.
Now, according to calculations, the 7:37 guchha is THE best for the tires...and the 9:37 is LIKELY to be somewhat underpowered for them. However, the proof as they say, is in the pudding. Soooo...we're going to give the 9:37 guchha at least one shot to prove its mettle with the wheels. IF (and ONLY if) it works out OK, the current tubes of the Phantom (Series 60 tubes) are going to make way for diff lockable tubes (either 60, 70, or 80 Series ones)...and we SHOULD have a monster that locks diffs, when the going gets tough.
Let's see how this test works out!