It must have a transfer case. A transmission requires a pump for lubrication and without the engine running the pump doesn't run and therefore no lubrication and a burned out transmission. Additionally the Trans will spin and could cause the engine to spin also without an oil pump and therefore engine damage.
A transfer case does not use a pump for lubrication, it is self oiling so it can spin. In neutral it spins when towed but does not transmit energy to the transmission as long as the Trans is in park or in gear.
That is why you can't tow a vehicle that does not have a transfer case.
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