Rear Limited Slip Differential 68cj5v6

I just discovered my cj5 has a limited slip differential in the rear axle. Common? can it be rebuilt? what Fluid is best when servicing it?

 

I believe it can be rebuilt with a Dana Spicer 22233X kit. Available for around $65.

 

The limited slip rear differential was a very popular factory option. In 1968, Jeep offered the excellent Dana PowrLock unit, which is both strong and easily rebuilt. Fill with plain gear oil, 85W90 GL-4 or GL5, and add a packet of friction modifier for limited slip differentials (LSDs). You can try half the packet at first, and add more if the axle chatters (makes popping noises around corners).

 

Is the friction modifier readily available? (I'm lazy and haven't looked ) What does it "do"? Make the lube "slippery-er"?

 

I don't know how it works chemically, but the clutch material needs it in order to slide smoothly. It changes the break-away friction coefficient somehow.

Wikipedia has a page - Friction modifier - Wikipedia

If you look for it at the parts store, it's there with the oil. You can get at least a dozen brands on Amazon, but they are all expensive (liike $15 for Prime-eligible brands). RockAuto has 3 or 4 brands for about $5; look under Drivetrain in the Universal parts category (tho you'll have to pay shipping or mix it in with another order).

 

Any Ford dealer will have it.

 

Bought last tube of diff oil modifier at Napa. Seems like it was anout $8

 

Similar to this

https://www.napaonline.com/en/p/NCB4285V

 

What about the fluid that is labeled for limited slip rear ends, is adding the modifier still needed? Or would adding it only be needed if you got the snapping/popping still.

 

AFAIK the modifier is still needed. It says "Limited Slip Compatible" which seems to mean it will not damage LSDs, not that it contains enough modifier to stop chatter. You can try it and see if your axle chatters. Won't hurt anything - just add modifier if you need it.