My manuals only let me down once, in a tight spot had to do a bunch of short (about 3') manuvers forward and reverse, basically left me in 2wd trying to negotiate a rock pile. Never broke one, but have heard of a lot of breakage with them. Manuals are just as prone to failure from my wheeling experiances. Especially WARNs, the hardware they use tends to be to hardened and snap easilly rather than give a little. For a while there was a lot of talk about where to get better bolts for replacements, but have't heard anything lately.