I have Rockcrusher diff covers, they are great on the trail, but they are held on with regular grade 5 bolts. No prob with the grade, but the bolt locations right next to the stiffening ribs can be an issue when you treat 'em like I do.



From right to left, front diff lower bolt, representative sample, rear diff lower bolt, and the cure.

I was really lucky these came off, the rock rash had ground off two flats on the front one, and the wrench barely caught and moved it. Had it been slightly rotated I'd been :censored: No room to use vice grips, and grinding on the bolt would also likely be grinding on the cover also.

The replacements are available at all local hardware stores, and are grade 8. Getting 20 is gonna be a pain, I've killed both nearby Lowe's and my local TSC to meet my needs, none left in any of 'em. They are in the drawers full of nuts/bolts that each store have, but are stocked by an outside contractor so there's none available in the back.

Size needed is 5/16" X 18 TPI X 3/4". Even if the head gets rock rashed, it's small enough to grab with vice grips if needed to remove. You can also order these in many variations such as with a nylon insert in the threads or different materials from McMaster-Carr for about $10 or so for a bag of 25.

Stock up now for your next diff fluid change, at least replace the bottom few most likely to see damage.

If you are not in a hurry (Shipping to Baltimore usually takes about 2 days) you can get these at MSC http://www1.mscdirect.com/cgi/nnsrhm
probably cheaper too!!!

Dave