Too much slip

[What's_nitro?]

Yeah I can't tell anything from those pictures...

I thought of something you can check- Make sure the side of the spur gear with the fiberglass friction pad inserts is facing the large end-cap of the diff. The flat side of the spur gear should face the large thrust bearing toward the small end-cap of the diff. If the friction pads are facing the wrong way it will cause the behavior you are seeing. Other than that I don't know...