Thank you Serge.

Tom has responded and looks like I will order from him.

I will install the unit myself. Its a question of getting the backlash correct and contact between the pinion gear and crown gear just right and I have the tools etc to do that.

I took measurements of backlash of the XJ diff I have before dismantling it.

John

 

I told Tom Lenthal that I would be installing in a 2005 XJR and he took no issue with that.

So I will be ordering the unit tomorrow.

 

You do well.
You seem to have the right skills and your purpose justifies biting the bullet.
I understand you won't regret it.

 

Ok order placed so now the waiting game.

A few posts back Cambo mentioned this:

"Actually if you take a diff from a 3.0L X350 XJ6 (not sold in North America, but everywhere else in the world) the diff is identical to the one from the XKR, same ratio, same part number in the bloody JEPC even... ditto for a 3.0L auto S-Type.."

So in Europe I wonder if the half shafts from the 3.0 would fit the Ford LSD and the 4.2 XJR wheel hubs?

 

Just arrived.

I did not have to pay import tax where as on my 200 cel cats from Paramount I did!

It should not take me long to install it into my already disassembled XJR diff.

Swapping my original diff out for this will be a longer job for sure and I have a 2-3 week trip up to MA to take care of as well.

 

It would be the same problem. I was just pointing out that although the QDF3W was only specified as fitting the X150 XK, it's the exact same diff used in X350's and S-Types.

This thing with the halfshafts is still causing me upset. I'm going to try and source some different versions and try to figure this out. It messes up my plans as well, I was planning to put a 4.0L S-Type diff in my XKR, it'd be the same problem...

 

If only kiloken was still active on the forum so we could pick his brain as to how he achieved this. I'm considering just biting the bullet and getting the quaife, would like to hear your thoughts of it jackra once it's fitted, I know Cambo said it made a huge difference.

 

I'm even thinking of one for mine (a Tdvi), it can spin a rear if you 'clog it' a bit coming out of a T junction and the power 'back-off' when it happens seems almost total.

 

I will start to build the differential today. I am taking my time not rushing this.

Will let you know how it goes.

Very good write up here https://www.jaguarforums.com/forum/x...lation-155867/

By fly2c.

That snap ring is quite difficult to get out to say the least.

 

Quick update.

The Quiafe is installed in the diff.
New bearings and races as well as axle seals.

Used old bearing centers without the rollers/cage as drifts on final part of
pressing the Timkin bearings on the Quaife.
The outer race is a little higher than the inner center of the bearing so you cannot simply press down on the whole bearing. Thats where the old centers proved useful.

Also used the old races to help knock in the snap ring once initially set in.

When I measured the backlash I got a reading of 0.0065

When using the yellow marker to check on contact between the pinion and the crown I got a very good "spread".

Tomorrow I will start to position the car ready to take out the original diff.

 

Another update.

With the cold weather my old bones do not last long working in the garage!

Anyway yesterday I finally removed the original differential quite easily I might add with my modified transmission support.
However at that point I realized that the original back cover is quite different from the one I rebuilt with the Quaife installed. See pics.

The one I rebuilt looks more like that of an XKR.

So I measured the turns at the axle when turning the propshaft flange one turn on each unit.

Both units were the same. Since there is about a 15% difference in ratios between the two, XKR vs XJR, I think I would have seen a difference.

Will install the Quaife differential today with any luck.

Because I undertook to replace the bushings in the rear control arms this has taken much longer than I anticipated and I am still waiting on 2 bushes to replace the incorrect ones in the kit I purchased.

Also see the pic of the splined shaft of the half shaft. Really hard rust in between the splines which made it so difficult to separate.
This was a waste of time anyway and I simply took the whole assembly out on the other side. Live and learn.

 

So I took the back plates off both.

The number of splines on the pinion gear and crown gear are the same on both units.

However the numbers/letters stamped on the face of the pinion gears are quite different.

Since the spline counts are identical there should not be an issue right?

 

Only occasionally following this thread so my comment may be stupid. Not the first time. To your question, is the overall diameter on the pinion gear and crown gear the same and are the gaps in the splines the same distance?

 

I will try to measure those diameters. Crown will be easy but pinion I will see how far it is from housing.

My thoughts are that the prop shaft will turn at the same rate with either unit and I should not get a reluctor half shaft error.

 

what are the numbers? I can check to see if one is just superseding the other

 

VH2872R8DAARAR

VH2872R8DBA1??

Unsure of last two digits in the "xkr like" casing.

also on a small sticker I just noticed the "xkr like" casing its says in very small print 2.87 ratio.

I have already replaced the xkr back cover with my original.

The crown rings are exactly same distance from casing and the pinion gears as best I can judge are the same distance from casing as well.

I am hoping this is much ado about nothing!

 

wow sorry Jack. No luck finding either under those part numbers. literally nothing comes up on google.

 

The thing is I do not know what the first number/letter is in the sequence.

 

Finally done!

With cold weather and waiting for parts I have finally finished installing the Quaife diff as well as most bushings etc in the rear suspension.

I parked the car in neutral with the hand brake off and disconnected the battery.

That way I could turn the prop shaft by hand to facilitate bolt access.

Installing the diff was not too difficult.

Had to tilt the front up about 20 degrees or so to clear the rubber balance ring on the rear of the prop shaft but once that was negotiated in it went.

Installing the half shafts was very easy.

To nudge them in the final inch or so I used a plastic pipe and large hammer to hit the inner metal edge of the half shafts.

That pushed the circlip on the end of the splined shaft into its proper position in the diff.

I had to bleed the rear brakes so made my own cap to fit on the brake reservoir for a pressure bleeder.

I have a new cap on order as the brass fitting on top of my original cap will not clear the cover over that area.

I do still have slightly mushy brakes so will bleed them again. I may not have pressurized the pressure bleeder enough.

Some brake fluid came out at the caliper but then stopped when I was doing the procedure. Same both sides.

Also the rear of the car is sitting too high.

Okay so the verdict after a short test run.

In sport mode with traction control off the car accelerates noticeably better on kick down. Thats a seat of the pants estimate.

It does considerably better when accelerating from a stop and taking a turn on to another road.

Was it all worth it. Maybe but not convinced. Thats my opinion.

 

I have been contemplating going the LSD route for my XJR for while now. I even obtained a quote from Green Cars.

My traction issues seem to have improved after I installed my new wheels and tires last week. The interesting thing is that the previous tires were Yokohama's Advan V105 UHP summer tires. Now with the cheaper all season tires I get better traction of the line. The Yokos had plenty of tread left so I am pleasantly surprised.