I have a shudder shifting btwn 3rd and top, on light to medium throttle. I had 15K service done and they (not a dealer) didn't use the LSD additive. After this service the LSD was slipping when cold; taking right turn at end of my street, revs would rise then bang, it'd go into gear and lurch fwd. I put additive in at about 20K, now has 26K and shudder still there but slipping gone. It is only mildly annoying & I'm wondering if different oil will fix this, or could it be damaged. Hoping if latter the dealer won't give grief.