Help identify this Jag IRS differential please

[BlownMGB-V8]

This is from a Salisbury housing, similar in most ways to XKE and XJ6 up through series III, however it has several notable and important differences

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The brake caliper uses an aluminum attachment bracket.

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The Power-Lok posi housing carries a pressed on trigger wheel, but there is no pickup. I have seen reference to an aluminum cover with a pickup for the speedometer and that could have been changed and left on the car (very likely). This ring is easily removed if not needed.

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And most importantly, it carries a ring gear that is attached with 7/16" bolts rather than the smaller 3/8" bolts used in all of the earlier units. This change alone is very important because not only does it add a great deal of strength, it makes the ring gear consistent with all of the rest of the garden variety Dana 44 ring gears used in a tremendous number of axles. This gives a great deal more selection in gear ratios and differential units.

I would like to know what car it comes from. This particular unit not only had the power-lok posi but also a 3.54 gear set, apparently a relative rarity in Jaguars.

Jim


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[rickbondy]

I have a '69 E-Type and it is not from it. Looking in all of my Jag books though the best place to focus is a 1988 XJ-40 Eurpoean Model. They came with a 3.54 gear and  power lock, unlike the US models which were open. XJ40s also  used a transducer mounted on the differential for the speedometer. The XJ-S used a Dana differential.

Good hunting,

Rick Bondy

[BlownMGB-V8]

Looks like I made one mistake, the 7/16 ring bolts are standard Jag and Dana 44 uses the 3/8" ones. Oops!

According to one reference I have, the XJ40 used an entirely different mounting system that has a couple of very large round bosses that extend rearward from the back of the case, and have nothing in common with the earlier design which is basically derived from a Dana 44.

This one is the same as the XK type. I mainly want to know about the brakes.

Jim