Hi there, I've really struggled to get the right grade of Diff oil for my Jeep here in the Uk, but I've finally sourced some. The only thing is I've read that the diff oil may need to have Friction Modifier in it as my Jeep is a Quadra-Drive. Is it Fact or Myth ??.


The next problem I've come across now is if I do need it, I'm not sure if its integrated into the oil I purchased already, so I'm hoping if I name the oil, someone might know,--Castrol Syntrax Limited Slip 75w-140--


Appreciate any and all advise, Cheers Jase

 

Just from the name I can tell it's a synthetic lube with friction modifier in it. You may need to add additional friction modifier to eliminate binding, but you'll know if it squeaks when you drive it. I use Valvoline SYNpower full synthetic 75W-140 in my open rear diff and it has friction modifier in it as well.