Series 1.5 4.2L diff swap

[Freoway]

I have damaged the diff on my Australian delivered 1968 Series 1.5 4.2L. I believe it has a 3.07:1 diff. I need to confirm. It had insufficient oil in it. A shocking oversight! Because there are not many Jag E-type diffs floating round, can I transplant a similar ratio diff from another Jag, like a Series 1, 2 or 3 XJ6? I presume I would only need the diff centre and not the housing. I'm grateful for any advice. I realise that there are some differences in brakes etc. for various models, so I'm hoping I can swap out centres. And maybe someone can teach me how to kick myself!

[Ruurd Schut]

I changes some years ago to 2.88 from Jaguar-XJS, very happy with the result.
At 130 kmh low revs and improved petrol consumption, no problems with acceleration, just fine.
These diffs are more commonly available, you also need the rear calipers from XJS which is an improvement as well. Some may say that 2.88 is too long but for me it is fine.

The only problem I had was charging with the generator due to low revs, solved by changing to a modern dynamo in the old Lucas housing. I guess you already have a dynamo.

Once again, the 2.88 is fine. The alternative was 5 speed gearbox as I wanted lower revs at cruisig speeed

[Freoway]

Thanks for the advice.

[mgcjag]

Yes you can use an xj6 diff...note that the diff mount brackets are specific to E type so make sure you use them if you swap diffs.....I also think you can swap the internals but confirm what you want to do with a diff rebuilder...Steve

[RICHOT]

I also had my E diff changed to a 2.88 ratio one from an XJS, I believe.

And, I also have a 5 speed box fitted! —- 5th gear just really becomes used as an excellent overdrive.

Makes for a great touring car .

Cheers, Richard

[44DHR]

Lloyd,
With regard to Steve’s reply #4, he is referring to the Inner Fulcrum Mounting Brackets which bolt into the bottom of the differential and determine the correct drive pinion orientation within the Rear Suspension cross member - or “cage”.
Irrespective of what different model Jaguar IRS you may potentially source, these will be required to be shimmed when bolted to the differential to permit correct alignment of the Inner Fulcrum Shaft to pass through and exit the cage’s reinforced entry points on each side.
Cheers,
Dave

[Series1 Stu]

I could be wrong but I'm pretty sure the Series XJ's don't have a limited slip diff.

It depends what your problem is and what you have damaged.

Regards

[mgcjag]

Just like E types it depends on the model...some Xj.s have lsd...some don't...Steve

[RICHOT]

I should have made it clear in my earlier post that I had the 2.88 ‘internals’ from the XJS fitted into my original diff case, ie it wasn’t the complete XJS diff unit.

Cheers, Richard

[44DHR]

Lloyd,
The common swap here in the UK is to use the 2.88:1 differential, (diff), from a Jaguar XJS. It gives better brake calipers and better oil seals in the output shaft bearing housings which are also improved with taper roller bearings. See some of my previous posts regarding Jaguar diffs for some more details on the various iterations of Jaguar diffs.

I prefer to check over the whole diff casing and swop out completely, rather than removing the internals, which can be time consuming to correctly set up. Generally, if they have been correctly maintained and the correct LSD oil used, they are virtually bulletproof. Here is one I have done for a Series 2 E Type.




With reference my post #6 above. These two photos show why you have to swop out the Inner Fulcrum Mounting Brackets. The first shows the XJS diff in the E type cage and how the Fulcrum shaft cannot line up with the XJS brackets fitted as these are a different angle. The second photo shows the E type brackets fitted to the XJS diff and how I have shimmed them to suit the E Type cage. The copper pipe shown is just simulating the bearings and seals width.





Regards,
Dave