This is what we use for synthetic, it's from a MAJOR BRAND NAME such as Kendall, Pennzoil, Citgo, or Valvoline and we have trusted them with our lubricant needs for the last 25 years with NO PROBLEMS! Top quality products from Major AMERICAN SUPPLIERS brought to you by RiversideGear. 75W - 90W FULL Synthetic gear lubricant for todays demanding differential lubricant needs. You will recieve top quality BRAND NAME SYNTHETIC LUBE from one of the above named manufacturers, we cannot promise a certain brand based on availablity to us.