It's not as trick as running working Lockers, but Silly Putty and Silicone Shock Oil let you make a limited-slip goo to put in your spider gears. Works on 1/10 crawlers.
http://www.scale4x4rc.org/forums/sho...y+differential
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Shoegoo / e6000 glues work well in the spider gears also. It starts nearly spool, then opens into a limited slip after a while
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With enough runtime either of those will start to open up more, but i'm pretty sure LittleGiants said he'd gotten years of service on his basement haul trucks before needing fresh.
Plus you can keep from using up more channels, not having to remember which way is open or spool.