Well, I didn't exactly get the info I needed here. I ended up buying a complete diff from a new 4.6 and hoped it would fit. I did not fit. The only difference is the dogbones won't go into it(too small). Thankfully the internals were the same but I had to take it all apart again to make it happen. I can say that the Savage suck to work on and is poorly designed. The AE Rival is by no means perfect but now that I have had a chance to own, drive, and work on both I can honestly say that I feel the Rival is drastically underrated compared to the Savage series. Its easier to work on and way handles better. The AE Rivals major downfall is the crappy electronics. They should either offer it as roller or put some real electronics it so people don't pay $175 more then they should just to have to throw them away and buy better stuff. Down the road I could easily see letting go of the Savage in favor of another Rival.