When I first read postings about Hub Oil being good, I purchased some. After reading later posts I shelved my purchase. The label says for Transmissions and Rear Ends, so I put Hub Oil in my 29 and 31. It made mine shift much better. My 29 has A Ryan overdrive known to be noisy, sure did quiet it down. On the 31 I changed the trans and rear it also shifts better! Hub oil does not appear to be as thick as STP but thicker than the old 600 I drained out.