Sorry for not responding for awhile, but a family emergency took precedence...
Let me address some of the concerns with the scenario here. As one of the posters pointed out, the three major axis nations war aims were not coordinated, and they often fought towards conflicting objectives. Many scenarios have been based on this (Japan attacking USSR, Germany not declaring war on US, etc.). I haven't really seen any scenarios where they actively coordinated and worked towards common objectives. I think this opens up some interesting possibilities.
First of all, while USSR is fighting for its life, I am not so sure they would attack Manchuria in an extensive manner. They were fighting for their life against the Germans, and opening a new front with a horrendously complex supply line with the Germans at the gate of Moscow seems ill advised. Plus, while they pummeled Japan in earlier clashes, they were playing defense against Japanese forces with few good offensive weapons. Attacking and invading Manchuria is another prospect. Japan excelled at fanatical defense. They would likely have needed significant additional forces. It took a full month after Germany surrendered for USSR to begin attacking Japan. That wasn't because of a hangover.
In this scenario, USSR is getting few trucks, locomotives, and food from the US. This means diverting urgently needed manpower to try and manufacture them on their own and increase food supply. Therefore, the soviets have fewer divisions facing Germany. Also, they will have to keep their armies in Siberia. While they may have stopped Germany from taking Moscow, I doubt they could have encircled von Paulus in Stalingrad. This means oil shortages.
The British fleet will be stretched much thinner trying to protect its vital supply routes in the Indian ocean. This will affect its oil availability and the supply routes to Montgomery in Africa. It will have to face down and engage the Japanese before it can really hope to counterattack and keep Rommel out of Alexandria.
Japan will be stretched to the breaking point, assuming she is successful at holding Ceylon (which was attacked in WWII, btw) or the Maldives. This is a huge gamble for Japan to divert part of its fleet to such a distant but vital role - not only its battle fleet but its supply fleet. I agree that Ceylon will be tough to conquer and hold, as will the Maldives and especially Diego Garcia, but doing so prevents a strong British presence in IO except near Madagascar or east african ports. Also, an earlier poster was correct in that the damage done at Pearl will have to be amplified to push US back to its west coast and make them start reconquest from a further point. A third and even fourth attack on the drydock may need to be risked. And possibly an earlier attack on the US carrier fleet not in Pearl.
Germany will be in a much better position, so they will obviously be indebted to Japanese who will have to face an additional enemy plus the US wrath. Not sure how this happens except with additional technology or cooperation of Uboat fleet in IO with Japanese Navy. May also have to promise if USSR is defeated to provide Oil to Japan through USSR.
Not sure what this means to Italy. Maybe in the war longer or even more active Navy given reduced British strength in Med.
Of course this may make the war end sooner as well as Japan is ridiculously overextended.