Hi everybody,

I just got a 1986 XJ6 and am starting to slowly work on it whenever time permits.I will start with the rear end which is a factory open one but i also have a XJ40 2. generation IRS with a locking carrier in it. So my question is, can the carriers be interchanged so that i have the advantage of a lock in the XJ6 IRS?

Thanks for any and all info,
Mustsed

 

I don’t have the answer to that particular question, but i just redid mine, it’s basically an Dana 44, so parts are available to do gear swaps and different kinds of carriers, I did an auburn limited slip and 3:73 gears, massive difference!!

 

You'd be better off looking for a similar year XJ-S diff as they are ALL limited slip.

 

Whilst the diffs may be swappable, the carriers aren't as far as I know. However not just the diffs are swappable. The later XJ-S cars used the XJ40 outboard brakes which makes maintenance so much easier.

 

I've heard that they do, but be aware that there are different carriers for the 2.88 ratio and the others, and they don't interchange. The ring and pinion do not interchange, unless you cut off the locating pin on the pinion.

Search on the XJS forum, as there are some there who have done it, I think Warrjon has done it.

 

1.generation IRS internals because i did a few irs swaps into other cars and mostly used the gen.1 irs because of the availability even over here and ease of installation! 2 of the swaps (one is my own 67 Mustang) i did the outboard brake version by mixing the center section from a 1.gen with brakes from a 2.gen. The only problem was the control arm inner bushings wich i did from a kind of delrin.

The stock Spicer Jaguar diff carrier has not 2 but 3 breakdowns for different ratios.

Mustsed

NOTE 04/09/10 It was recently brought to my attention by Sedat Yalcin that the above information only applies to Dana 44 carriers. If you are using the original Jaguar carrier you need to be aware of three different carriers. The 2.88:1 carrier will only work with 2.88:1 ring and pinion. If you have a 2.88:1 carrier and want a lower ratio you must change the carrier or buy a custom "THICK" gear. After getting this information I confirmed it by contacting Mike at CWI and he added that Jaguar made there break between low and midrange ratio at 3.54:1 and 3.76:1. The important thing to keep in mind when deciding weather you need the parts set up for high or low ratios (excluding the 2.88:1) is not weather the carrier is Jaguar or Dana 44 but weather the ring and pinion are Jaguar or Dana 44. If the ring and pinion is Jaguar, regardless of weather the carrier is Jaguar or Dana the break in ratios is between 3.54:1 and 3.76:1. But in reverse if the ring and pinion is Dana, regardless of weather the carrier is Jaguar or Dana the break in ratios is between 3.73:1 and 3.92:1.

Taken from the IRS forum run by Daze Scovel. I took this part because i am Sedat Yalçın who brought this up.

https://irsforum.boardhost.com

 

The XJ40 diff casing is not the same as the earlier casings, they are not useable in a Series III or earlier saloon. As to internals, the carrier, no idea.
As far as the internals go, i.e. the carriers, the different ratios require different sizes of crownwheels, in particular the thickness of the crownwheels is different. So to accommodate this, the carriers have different depths. Usually there needs to be only two depths of the carriers (i.e. only two versions of the carrier) as there is enough adjustment possible with shimming the pinion and the crownwheel, to need only two versions of the crownwheel to accommodate all the required ratio changes.
So providing you do not make a ratio change that goes across the divide between the two versions of the carrier, your original carrier or a replacement for it, will be reuseable. If you do, it will not be.
An XJS diff from a V12 will have a 2.88:1 differential which will be too highly geared for your saloon.
In case it is of interest, if you wish to have an LSD, the most straightforward way to do it is to use your existing diff and swap out the carrier for an Eaton TrueTrac. I have done this on my XJS and it is absolutely fantastic, far far better than the OEM LSD.
The procedure is straightforward, and if your existing diff is leak-free at the pinion seal, requires no changes to the pinion at all. It is a matter of lifting out the old carrier, bolting the crownwheel to the new one, and replacing it with the TrueTrac. Only shimming of the carrier position is required, which is not hard at all.
This link is how I did it, but as mine was a DANA diff, and yours will be a Salisbury, the output shaft stuff I write about is not applicable. Luckily for you the Salisbury output shaft setup is far easier to rebuild, should that be needed, which I doubt. Similarly the output shaft spline count on the Salisbury is not the same as for the DANA, but the TrueTrac comes in both counts.
https://www.jaguarforums.com/forum/x...tified-229645/

 

Thanks Greg, great info.

Will be out on town for two weeks and get into it after coming back.

Mustsed