If your looking for easy and cheap limited slip action, have a look here. http://monster.traxxas.com/showthrea...highlight=diff

If your wanted to seal the stock diff yourself so you can tune with fluids then look here. Especially have a look at the link in post #30 which shows a larger picture of page 133 in the magazine that he posted. http://monster.traxxas.com/showthrea...leville+washer

More details of the above sealed diff mod. http://monster.traxxas.com/showthread.php?t=486792

And 2 more diff links for the heck of it. http://monster.traxxas.com/showthrea...leville+washer and http://monster.traxxas.com/showthrea...ht=sealed+diff

Don't be afraid to check out all the links as there is a lot of good info in each of them.