So Im building my Hellfire ss kit. Got the diffs together, however when I put them in the housings theres a good bit of play between the pinion and the diff. Ive already tried taking it apart and rebuilding it. The kit didnt come with any extra shims, so i assume im must be doing something wrong...your help is appreciated!

Also the diff cases are plastic? Can I use the alloy cases from a savage x.

You could be putting them in backwards, The will only fit one way round

Jack