I had the same problem, it was almost like driving with a spool. First make sure you have two thin plates like Dr. Diff referred to. Next when I took mine apart I could see scuff marks or light galling on some of the plates. I used a fine Scotchbrite pad in my small pneumatic angle grinder and buffed each disc and reassembled it using friction modifer [ NAPA sells Xtrack } instead of gear oil. Naturally you need to use at least one full tube of friction modifer when you fill the rear end as well. Now it works as good as any clutch limited slip can. Equal grip to both tires in a straight line with really good lock up and still enough give to go around tight corners without chatter.