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



The brake caliper uses an aluminum attachment bracket.



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.



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

[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