Probably beating a dead horse here since you seem to have had the question answered already but I have the HW Shockproof in my tcase and don't have any problems. Also, it's nice having MT-85 available now rather than having to mix 90 and 80...man I'm lazy :P. I have 75W90 in my diff and haven't had problems there either. Just make sure you use the correct amounts of each.