If you are blowing diffs, it usually means something is loose. It could be the ring/pinion mesh. Here's a good link to shimming diffs. This is for a LST2 diff, but it's the same principle for all diffs: http://hdrcvideos.com/forums/viewtopic.php?f=38&t=15380

Another thing that can cause diff problems is driveline slop. If the CV's and dogbones are all loosey-goosey, then when the slack gets taken up there is a slamming effect, and this shock is transferred through the whole drivetrain.

Your front diff takes a helluva beating, because when you land from a big jump or slam on the brakes, all the weight shifts to the front and then the front diff is subjected to lots of abusive forces. So it pays to make sure the driveline slop is at a minimum, plus make sure the diff gears are shimmed....



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