Topic: Differential ID 1966 K code.

[Frank Bullitt]

Hi All, I am after some help please. I am missing the axle data tag. I have the correct 9" axle for my K code.

The differential has been taken out of the axle casing and the door data tag shows the axle as an E code, When you decode this it says the axle ratio should be a 3L50 With a model code of WCZ-T.

The differential with a code E and a 3.50 to 1 ratio should be a limited slip diff. How can I tell if I have got a limited slip diff fitted?

[J_Speegle]

If I understand correctly then look to see where the ring gear is bolted to the carrier. IF the carrier has sunken areas surrounding where the bolts go through then you have a limited slip. If not then its an open


If you have the 3rd member out and visible
Open style on right

Not the only way but one of a number of quick ID features

[Frank Bullitt]

Hi Jeff,

Thanks for the quick reply, I believe I have the correct one but will look next weekend when I am back there.

Thanks again.

[midlife]

To prove you have a limited slip differential, the next time you have the car up on a lift, put it in neutral and spin one of the rear wheels.  I believe the other rear wheel will rotate in the same direction; if open rear end, it will rotate in the opposite direction.
I believe this is correct.

[Frank Bullitt]

Midlife, yes thanks but the diff is out of the axle casing at the moment!

[66TotalPerf]

Easiest way to ID limited slip on the bench is from Jeff's left 2 photos, the limited slip units have the bolt heads recessed into the casting. However, with the unit removed, wouldn't be a bad idea to at least test breakaway torque and if low replace clutch packs.

-Brent

[Bob Gaines]

Easiest way to ID limited slip on the bench is from Jeff's left 2 photos, the limited slip units have the bolt heads recessed into the casting. However, with the unit removed, wouldn't be a bad idea to at least test breakaway torque and if low replace clutch packs.

-Brent

+1

[RoyceP]

Typically on a 55 + year old car the differential is shot. At a minimum you usually have to replace all the bearings and clutches. Not everyone knows that you must also use Ford Friction Modifier with the conventional oil - do not use synthetic gear oil or the clutches will be toast.


If you are lucky the differential can be saved using the above but often the differential is cracked, gears are worn etc. Have someone rebuild it properly and you will not have to worry about it in the future. New axle bearings and gaskets are needed too.