Huh. I find that hard to believe. The 800 series were available with an LSD. That unit fits in the same form factor as the regular diff. And it's about the same size as the walker diff.My understanding is that gravely was asked why a limited slip clutch wasn't offered, and reportedly the answer was that it wouldn't fit. Or so its claimed by some. The next best idea maybe is finding a replacement parts set that makes it a "solid" axle I had a parts list for that once maybe somebody else knows.