Hi, I'm starting my planning work for installing a Quaiffe differential in my 2005 XJR. I'm thinking of picking up a spare differential and use that as the basis of my Quaiffe fitted differential and I'd like to ask if there is any difference in the rear differentials for the X350/358 series of cars. Can I just get any rear differential to use as a base for my swop or are there differences in the different rear differentials?

If there are differences between the different models of X350/358 differentials, can somebody advise as to which car model's differential is the same as the 2005 XJR's rear differential?

Thanks very much for any advice.

 

The stock diff in the 2005 XJR is the Visteon 8" with 2.87:1 gears, and it's the same diff as these cars:

X202 S-Type, from VIN M45255 – N52047; all 4.2L engines (S-Type R and normal 4.2L)
X350 XJ, up to VIN H31470; all 4.2L engines (4.2L XJ8, XJR, Super V8) the 3.5L is different

More info here https://www.jaguarforums.com/forum/j...ntials-134733/

Some cars in these VIN range may have been fitted with a replacement diff by Jaguar which is the newer GKN design and totally different to the Visteon 8", if you are sure that your 2005 XJR has never had the diff replaced then no problem. But it's worth having a look underneath the car to be sure.

There is another option and that is to fit the older version 8" from the 4.0L S-Type, the advantage here is that the diff center is a standard Ford 8.8" so you have many options for the LSD (plate/clutch, Torsen, etc) and they are usually much cheaper than the Quaife to buy.

However you also need to source the driveshafts from the 4.0L S-Type as well, as they are different lengths. And the gears are 3.31:1 which means the car needs to be re-programmed to accept the different ratio. This is a possibility now.

Actually I am passing through Singapore quite regularly for work these days, if you wanted to go down that road I can probably help you out with the programming on one of my visits.

 

Thanks very much Cambo. This helps greatly in clarifying matters. The next thing is to go through the details provided in other posts about the various seals and bearings to change also, to do everything at one go.

You come through Singapore every so often? it would be great to meet up. Do let me know.

 

Yeah I was in Singapore last week actually. Just for a couple of days that time. Our regional head office is in Tampines so I'm through there fairly often, i'll let you know when i'm in town next time.

Regarding the bearings and seals there are a few threads which cover them, this is a good one https://www.jaguarforums.com/forum/x...lation-155867/ but it does not include the pinion parts. I would personally leave the pinion alone unless the guy doing the rebuild is a proper expert. An incorrectly setup pinion destroyed my first diff with the Quaife in it.

There is another thread here where we also talked about the pinion bearings, seal and collapsable washer/spacer https://www.jaguarforums.com/forum/x...arings-102296/

 

Thanks again for all your comments. One other question, in reading the links you provided for the differentials. Does the 2005 XJR differential have a chip or black box in it such that I would need the dealer computer make the car recognise a rebuilt differential from another 4.2L X-350/358, or even if I take the original one out and rebuild it and put it back in?

I'm a bit wary of the computer these days as my indy's computer died and he hasn't replaced it and when I replaced my hifi head unit recently, the car conveniently stopped recognising my multi disc CD changer, although the head unit CD player is fine.

 

The X350 diff is purely mechanical, if you maintain the original gear ratio's then nothing is needed from the software side of things. You can swap diffs in and out, the car know's no difference as long as the ratio is the same.

Maybe we can sort out your indy's diagnostic system (and your CD player) when I come visit.

 

Great, thanks. That's nice to know. Do let me know when you come by again.