I picked up what i think is a trac lock carrier today but I'm not sure. I does have the four pins and its 28 spline, The part number is C6AW-4205-B and there are a couple numbers elsewhere but they are hard to make out except for MCC-22.

 

i think the c6AW is just the part number or casting number of the cast iron housing itself doesn't tell you anything about the actual unit itself(other than it is newer than 1966).


quick way to tell if it is posi or not is by the bolts holding the ring gear to the differential. if it is a flat surface then it is not a posi. if the bolts are recessed (spot faced) into the carrier then it is a posi unit.

only way to tell what it came from is by the metal tag that was bolted to the cover, but that is probably long gone if you just have the pumpkin itself.

even the non-posi diff came with 4 pins, so that is not an accurate way to tell.

rgds
Mike

 

This one has the half recessed bolts and looks way different than the open carrier i have.

 

The carrier has a different appearance, but is has nothing to do with a limited slip differential (posi-traction is a GM term).
C6AW = In 1966, Ford introduced 31 splined axles on LTD/Galaxies and T-Birds along with the 428 engine.

Even tho classified as a 9 inch, The ring gear is 9 3/8 inches in diameter.

C6AW = 1966/67: C6AZ-4141-B .. Rear Axle Differential Carrier Assy.~ 9 3/8" ring gear- extra large carrier bearings.

1968/69: C6AZ-4141-C .. Rear Axle Differential Carrier Assy ~ 9 3/8" ring gear-extra large carrier bearings.

The carriers are the same whether limited slip is present or not.

This is true for the 8 inch / 9 inch / and the 9 3/8 inch ring gears.

31 splined axles & the 9 3/8" ring gear were also available on 1968/72 F100 Camper Specials.

 

then you have the posi unit.

unforetunately the tag tells the rest of the story as to what it came out of.

good stout units.

rgds
Mike

 

Count the teeth on the ring gear and divide that by the number of teeth on the pinion gear and you'll know the ratio of it.

 

C6AW = 9 3/8" inch rear axle ratios offered: 2.80-1 / 3.00-1 / 3.25-1

What year is the rear axle from?

The ring and the pinion will have Ford engineering numbers on them...that will lead to the year they were used and the axle ratio.

The 9 3/8" rear axles were only used from 1966 thru 1969 on: LTD/Galaxie; Mercury Marquis, Lincoln Continental sedans. / 1966/72 T-Bird and Mark III;

 

It's a 28 spline unit. Heres a pic if it will help. The guy i got it from said it was out of a 68 Mustang, He narrowed the housing and went with a spool so didn't need it. I only give 50 bucks for it.

 

thought you had the whole pumpkin assemlby, not just the differrential assembly.

if that is the case and since you don't have the ring gear, just split the case apart and see if there are clutches inside.

if it is out of 68 Mustang, good chance it could be from a 8" rearend as that was the most common rear in those cars. only the bigblock cars and hi-po small blocks got the 9" rear in the mustangs. (unless of course the previous owner changed to a 9")

rgds
Mike

 

It's a 9", I saw the rearend it was out of, Tried to talk him out of that too. Guess i'll split it this weekend and see.

 

Well i called the guy i got it from and he said it was an Equa loc and said that it was the predecessor to the Trac loc. Has anybody had any experience with an Equa Loc?

 

Look in the end hole where the axle go's. if you look at the splines and see one side has what looks like 2 splined parts then its a posi. if the splines are 1 piece than it's open. If it is a 9 3/8 from a lincoln it will still fit a 9" housing if you notch the opening of the housing for the ring gear to slide into the hole. you will also need the carrier housing for the large bearings.


Rick

 

Yes it does on the short side. I have the housing, case and gears from a late 60" truck.

 

Well i took it apart today and it is an Equa loc, Now i just have to find disc for it, Equa locs have different discs than Trac locs.