I have been trying to figure out how to get shorter outdrives on the slipperential because they hit the steering servo mount in my 808. Mike mentioned that he thought the HB outdrives might work, but I ust tried them and they didnt. They work on the small cover side, but not on the large cover side. Its just a little to tight to get the cross pin in the hole. Strange that it works on one side but not the other.
What I did make work was the xray diff outdrives, but I had to replace all of the gears inside with the xray gears to make the outdrives work because it uses a different size cross pin thru the outdrive shaft for putting the crown gear on. It also needed to have a bunch of extra shims added to make it work.
I used all of the metal washers/shims that came with the slipperential, and then used all of the washers/shims that were in the xray diff too. So basically 2 shims behind each of the 4 satelite gears (1 xray washer and one slipperential washer) and then I put both of the xray washers that go behind the 2 larger crown gears behind the crown gear that went on the small slipperential cover side allong with the washer from the slipperential. (1 slipperential washer behind the crown gear inside the large cover, 2 xray washers and 1 slipperential washer behind the crown gear on the small cover side) I hope all of that makes sense. It seems to be a perfect smooth mesh now. I tried adding more washers to see when it got to tight and if I put more than this in there anywhere the mesh got to tight inside.
Heres a quick pic with the shorter xray diff outdrives and the xray internal gears installed. I think it should be good. Not exactly a cheap change to get shorter diff cups, but if you already have an xray then you have all of the parts from the xray diff to make the change. In the 808 you basically need the shorter outdrives because if you use the longer ones the outdrive hits the steering servo mount and you need to take quite a bit off just make enough clearance.
Anyway, just though Id post what I found to work.
Xray outdrives insatlled with xray gears shimmed up. Slipperential outdrives sitting next to it for length comparison.