I want to change the diff oil in my 05 rubicon. Apparently it needs to be changed every 12k miles. Sounds pretty lame to me but whatever. Anyway was thinking of putting in 75w140 synthetic. I assume this guy doesn't need any friction modifier? Should I consider just using the 80w90? This jeep is only used on pavement to get to the trail. It is not a daily driver at all.
Suggestions? thanks all!
I don't know anything about the Rubicon, except that a bunch of old retired-looking coots shows up every summer in Silverton with them now, but needing to change diff fluid every 12k miles sounds like it has limited slip clutches in it. I would be very surprised in that case if it didn't need friction modifier. Do you know what kind of mechanicals it has in it? When all else fails consult the Owner's Manual, and make sure you have the section for the identical equipment that you have.
Earle
You are fine with what you want to put in it, 75w140 SYN. Friction modifiers are for clutch based ltd. slip. You have a helical gear based unit.
tw
In that case why change the fluid every 12k miles? That's a waste of petroleum.
Earle
That is a 'schedule B' thing for extreme use. Not necessary for the average owner.
tw
LOL! Just living here in Canada is extreme use, according to the FSM
Anyways, go for the 75W140 Synthetic
4.0 pints for each diff 25 Ft/Lbs torque for the dra> Earle Hort>Yep, pretty 'all-inclusive', isn't it? Otherwise known as 'CYA'.
FrankW wrote:
If it were me, I would split the difference on the mileage schedules. Halfway between severe and normal should be often enough. On my personal vehicles, and I have 4 that are 4x4 I look at the condition of the lube and change it when I notice a discoloration.
As for lube, I have been using 85-140 synthetic for 15 years. My Cherokee has 240,000 miles and the Differentials are still going fine, not even so much as a pinion or axle seal problem. It is difficult to argue with that record...
Good Luck, Bruce
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