Mike the Radiator Man's
Tech Tip #5 , Anyone can have Traction (Loc) !


Anyone can have Traction (Loc) !

Have you been wanting a Traction-Loc in your 8"-9" differential? Have you found how difficult affordable used ones are getting to find? Then here is a way to turn your peg leg into a two striper.

Remove the differential carrier assembly from the car and remove the side bearing caps. Pull the differential case assembly out of the carrier, remove the ring gear bolts, and tap the ring gear from the case with a soft hammer. You will find 2 counter sunk screws holding the case together, these can be either Phillips slotted or recessed hex screws, remove them.

Once this is accomplished the case can be split in half. You will notice that the two halves have gears in them, three in one side and one in the other. These are the axle side gears (splined internally) and the pinion gears. The case half with one gear requires no further disassembly, the gear in it will lift out. The other case half contains the other axle side gear and both pinion gears held in place by the cross pin. To disassemble this half drive out the 1/8" roll pin that locks the cross pin in place and tap the cross pin out. The pinion gears are now free to remove from the case halves.

This tear down is required to gain access the axle side gears. Lifting out the side gears you will notice that between it's thrust face and the differential case counter bore is a thrust washer, Ford part number C9OZ-4228-A it measures .031 thick. The function of this washer is two fold, it is a hardened surface between the axle gear and differential case to prevent metal galling and, it spaces the axle gears at the proper engagement depth to rotate the pinion gears. By installing two thrust washers on each axle gear instead of one, the gears are moved inboard enough to cause the pinion gear pitch diameters to bind, effectively locking up the differential assembly.

This modification still has the ability of slipping some on turns, but will have a ratchet feel similar to a Detroit locker. The washer trick works equally well on both 8" and 9" rears. I have done several of these for street and strip cars and I believe you will find the results rewarding.

Mike the Radiator Man




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