Differential Identification

Nov 3, 2002

I need help identifing what 3rd members are in my FJ40, and What model number of ARB to replace them with.  

To start with,  this vehicle was inherited so little info is known...

The FJ has full floating front and rear axles with 12" disc brakes, F/R both 30 spline, 1.31" diameter axles. 12 Bolt Ring Gear on Both. The rear axle is offset to the passenger side.

The 3rd member cases are both casted with the number 60011.

The current differentials are both some kind of limied slip with a milliron small gears and weights (and BOTH are broken, parts are laying in the axle housing)...

The ring gears (F/R) have 37 teeth and are 9.25" in diameter measured at the very outside of the gear. Pinion gears (F/R) have 10 teeth.

Are these 3rd members the exact same (quick measurements are identical)..????

If so, do I then order two of the Same ARB number..??

Lodi, CA


Staff member
Jan 15, 2002
Toquerville UT
if you are SURE the rear is fullfloat, then they are identical. If the rear is c-clipped and semi float, then I would order both SEMI float ARB's for interchanability should something unforseen hapen.

Fullfloat rears are quite rare in the US...
Nov 3, 2002
I'm sure Brian....  I have four wheel disc brakes and the rear axles can be removed by removing the six hub lock bolts, removing the hub lock, and then pulling gently on the axle....

I had to machine Rulon sleeves for the rear spindles to act as oil seals, as this conversion that was done to this axle did not make a provision for a seal...

Both of the rear axles appear to be custom, the use of the "Marlin Tack" occurs on both ends of each (both ends are splined) as there is nothing else to keep the axles from drifting in or out.



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