I did the diff cup mod and have been running the truck for 3 weeks now tih no problems......Just use any 3/8 inside diameter brass or copper pipe dremel it out to fit over the outdrives snugly, cut it to lenght and add some ca glue and tap them on.........I could not find the compression fittings at my hardware store, so I just found some little peices of brass pipe 3/8 inside diameter about 7/8 inches long, I dremeled the inside out cut them to lenght then had to grind down the shock towers a bit so they dont rub on the brass sleeves.