The POD which enables Japanese participation needs to be profound enough that there is no embargo with the USA. So, Japan's follow up invasions in China after Manchuria pretty much have to be butterflied away (how?) Perhaps the USSR is more aggressive in Manchuria, stoking fear in Japanese ranks that expanding the war in China before securing the north is a bad idea. And so, Japan expands north as a way of securing their flank for future endeavors in China. In this event, the Japanese invasion of the USSR would be quite muscular. The resource drain in the east would be larger that OTL (as the only way to make this TL work would be for the USSR to be more aggressive about Manchuria's borders). When Barbarossa goes of ITTL, the Germans are helped a bit. The USA, perhaps due to more instability during the Great Depression (no switch in time to save 9, court packing goes through) does not look to send aid to the USSR or trade with them, to avoid war with Japan for the moment. Aid sent to Britain is just for Britain, and so it is up to the British to send supplies to Russia.
Germany won't win, but they will almost certainly get 2 out of 5 of the following: Leningrad, Rostov, Moscow, Sevestapol, avoiding heavy losses in the winter--roughly in order of likelihood. This changes things big time in 1942, even if the USA gets buyer's remorse and issues an ultimatum to Japan to stop expanding their war against Russia. Japan rejects this and does an ATL Pearl Harbor, Philippines invasion, etc. Germany likely strikes for Stalingrad ITTL, logistics are no better so they may succeed but they're not capturing Baku...even Astrakhan is 50/50 ITTL. If Leningrad did not fall already, it would by that winter, as the Russian counteroffensive would not be strong enough ITTL. Pretty much, if USA is not in the war against Germany by the end of 42, which they probably will be, USSR is done by default.
Beyond this point USSR stumbles on, even if Moscow falls in 1943. Germany ends up getting nuked. Japan gets nuked next. USA is more powerful in this Cold War scenario, USSR would be a regional power hedged in by Balkan and Eastern European countries under western sway.