Diff fluid recommendations

[BobSacamano]

I’m about to install my “new” 8.8 4.10 limited slip rear end. I thought I would go with the recommended 80W90 gear oil with friction modifier.. I see Castrol makes this gear oil with the friction modifier already added. Does that sound OK? I don’t do any heavy towing. Or should I go with a heavier oil since it is used?

 

[scotts90ranger]

I wouldn't overthink it too much, standard gear oil then adding modifier is fine or the synthetic stuff with the modifier in it already, either works fine, it'll appreciate just having oil

 

[BobSacamano]

I wouldn't overthink it too much, standard gear oil then adding modifier is fine or the synthetic stuff with the modifier in it already, either works fine, it'll appreciate just having oil

OK. You’re right. I probably am overthinking this. I just wanted to make sure I was doing what was appropriate. It’s been a learning experience dropping the axle in my driveway and putting the new one in by myself. Ha ha.

 

[BobSacamano]

4 ounces of the friction modifier or should I do two and see how that goes?