I have an 84 Bronco II with a traction lock rear end, I was woundering what fluid I need to change the old stuff out with?

 

Hypoid Gear lubricant, Ford Part #E0AZ-19580-A, with 4 oz. of Friction Modifier Ford Part# C8AZ-19B546-A (or their equivalents) for the 7.5 rear axle.

Hypoid Gear lubricant, Ford Part #C6AZ-19580-E, with 1/2 oz. of Friction Modifier Ford Part# C8AZ-19B546-A (or their equivalents) for the Dana 28 front axle.

More info

 

If you want the Trac-Loc to grab a little bit more don't put the friction modifier in. What that stuff does is make the gear oil more slick. and if you don't use it the friction disks in there will grab harder. And it wont harm the frictions or the rear end if you don't use it.

 

Actually, the friction modifier keeps the clutches from slipping. Not putting it in will burn up the differential. Buddy of mine burned up 3 different Ford 9" Trac-lok diffs that way.