Originally Posted by
Chuck 21
Heres your problem with your slipper.
#1 you put the washer under the wrong end of the spring.
Take your slipper spring off and look at the shaft. You will see the shaft
has a cone tapper just before the threads. Looking at this you will see the
spring retainer bottoms out against the cone before you can get max
tension against the slipper. So putting it at the wrong end as you did makes
the problem worse. The washer needs to be on the aluminum slipper plate
not the nut end.
So what I did was go to Ace Hardware in their nut and bolt department
they have a chrome & black chrome nut/bolt/washer section. There is a
chrome & black chrome washer there that fits the outer slipper hub
perfectly for shimming the spring. Take your outer slipper hub with you
because thanks to the chroming prosess some fit better then others.
Now you will keep your slipper spring free to put max tension against the
slipper pads instead of making the problem worse like you did by putting
the washer under the nut.
This works great, I have fixed many SC10 4x4 slippers at the tracks I race
at this way. At the track I don't have these washers with me but a quick
fix at the track is to take the blue aluminum servo arm retainer that most
people have laying around in their tool box and use that till you can get to
Ace Hardware to get the correct fitting washer.
Good luck, I hope this helps till AE gets this fixed along with everything else
they need to fix on the SC10 4x4....
BTW: AE if your listening, you need to make a longer & stronger slipper
spring for the SC10 4x4 (I'm sure you know this already though") 
Adding a washer does nothing. if you add a .020 washer you will loose .020 on the nut side and end up with the same tension. a compressed spring is a compressed spring whether it has a washer at one end or not.. i even had a conversation with don @ AE about the spacer being machined wrong. i ordered some washers from mcmaster carr for spacer it out more and i get the same results. everything moves out on the transmission shaft but you still end up with the same tension. if i tightened nut to 3.5mm before then after added washer i can only tighten to 3.3.. but i still have the same weak tension that allows it to slip to much. the 550 motors tear up the slipper pads. /End