I previously posted that I took one of these apart. Unfortunately, I didn't photograph the process, but suffice to say it was pretty easy and didn't require any special tools.
Basically, there are three major parts to the assembly; assembled horizontally. The oil is sealed inside with some silicone sealant, no special gaskets or huge o-rings.
Before taking it apart, I'm going to show the electrical connectors. First are the position and temperature sensors. The 6-pin connector is for the resolver, the 3 pin connector is for the temperature sensor. According to Toyota, if the ECU determines the temperature is too high, it will shut down the MGR until it fall back into the proper range.
This connector is the main 3-phase power connector. Note that this part is some sort of extension to the main connector.
Locating these plugs (both data and main power) could be a real PIA, especially if it turns out Toyota is the only source.