Dumb Axle Question

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Kermit 460

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OK Guys ,

I"m trying to get rid of my open 2.75 rear end thinking I want a 3.50 trac loc.I know a few 9 inch rears for sale out of cars lying on the ground.How do you identify a real trac loc axle ,something to look for on the tag?

 

midlife

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If the tag attached is correct (often times they are not the one appropriate to the rear), look for 3L50. L indicates a trac loc.

 
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I could not tell you on the tag, but if you prop it up and turn one wheel and the other wheel tuns the other direction it is an open rear end, if they turn the same way it is a trac lock.

as to ratio, you can count the turns of the yoke for one turn of the wheel for a fairly close estimate.

 

72HCODE

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ok going off memory.

the Ford 9" open diff does not have recessed bolt holes for the ring gear.

the Ford Traction lock has recessed bolt holes for the ring gear.

open diff left,, traction lock right

bn2.jpg


traction lock ring gear bolts are 5/8

open diif ring gear bolts are 3/4

some other things to consider: if you are just going to swap the entire axle then rebuild the traction lock with the axle it came from, no problem.

if you just want to swap out the unit, make sure you match the number of splines you already have either 28 spline or 31. most open diff cars came with the 28 spline unless it was a big block car.

you can also buy a new Ford racing traction lock in 28 or 31 which might be cheaper in the long run.

if you choose a junk yard diff it may cost you 300-500$ in repairs verse buying a ready to install new one for the same price.

with a junk yard unit you might be walking into a hornets nest. the traction lock could be cracked/warped, have major corrosion damage.

the shafts inside might be completely worn out at minimal it will need new bearings and clutch pack rebuild, then you open it up and find all kinds of surprises.

if the axle is complete and you don't trust the tag, if you hold the yoke and spin one side the open diff will just spin the opposite side.

if you hold the yoke on a traction lock and try to spin it, both sides will act like a spooled diff and the yoke will want to spin. it takes a pretty good amount of force to force a traction lock to spin both tires opposite directions without the yoke spinning. about 120-150 pounds on a torque bar to make a traction lock chatter. if you have a known traction lock and put wheels on it and try to spin the tires in opposite directions and it breaks loose easy then you know the clutch pack is gone or worse damage inside the unit. if the unit is on a junk car that is off the ground with trans in park an open diff will spin the wheels in opposite directions easy. a traction lock will force both tires to spin in the same directions forwards or back with the trans in park you won't be able to budge it, with the trans in neutral both tires will spin in the same direction easy forwards or back.

 

Kermit 460

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Thanks guys !:)

 

Blueoval71

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I just upgraded everything so I have a 28 spline unit I no longer need. It probably has 50k miles max of regular driving on it.

 
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