i have a '98 4runner ltd and recently tried to use the read slip diff to pull a boat out of the water because it was tougher than usual due t a low, low tide. i don't think it worked as the light didn't remain on and i still had slippage. any suggestions? thanks.

I dont know what the light means, but you can still have slippage the surface is loose enough. However, it should be considerablely less than w/o the diff lock on. You could always test it by having a couple of friends on either side watch the rear wheels. Check the manual, maybe there are some necessary steps to lock it (e.g. put in park or neutral, etc.)