Could someone tell me what the gear ratio is for a diff in a 95-97 XJ6??
Thanks

 

The 4.0 X300/XJ6 with auto trans (and the X305 with the 6.0 V12) the diff is 3.58 ratio

Cheers
DD

 

Sadly, those USA models were not offered with a limited slip diff. Sure would like it, esp in the XJ12. Only the XJR and XJS got it, AFAIK.

 

I have seen VDPs with the LSD. I don't know if any or all V12 cars were fitted.
Sometimes the cars get a replacement and a different diff gets installed.

I have a limited slip in my 1992 XJ40 but I installed it myself.

Look on the tag on the diff and it should be a red/yellow for 3.58.

If it has a BLACK 'X' through it it IS the LSD version.

bob gauff

 

Old thread, I know, but my pedantry must be assuaged. The "Vehicle Care" manual states it's a 3.54, not 3.58 rear end.

 

I've seen that spec too John, don't let it get to you! It is a small difference. I wonder which one is correct? Someone with a diff in their hands would be able to find out. At any rate, the XJ12 should have been built with the 3.27 Powr-Lok. I'm pretty sure the older V12 drivetrains had LSDs or at least as an option.

I hate those stupid trade names that are made up of misspelled real words that is somehow supposed to describe their function.

 

I'm certainly not fussed about a ~1% difference -- that gets dwarfed by just tire wear. I just want my (future) Cars&Coffee 'brag sheet' to be numerically factual.
That said, I have no idea whether the Solars I have actually came off a 2003. Mental note, look for datestamps next time they're off.

 

The Jaguar parts catalog for the X300 shows four available ratios, 4:09, 3:77, 3:58, and 3:27

Go to item #22 here:

https://parts.jaguarlandroverclassic.com/parts/index/part/id/922.1585.5727.24373/brand/jaguar/


The XJR/6 used the 3:27
The V12 used the 3:58 as did the 4.0 normally aspirated/automatic
The 4:09 and 3:77 were for 3.2 and 4.0 normally aspirated with manual transmissions, respectively

I have seen the "3:54" in some publications as well.

I'm reminded of a similar situation with the specs on the older Series III XJ6 diffs. The sales literature shows 3:07 as does some service literature. The parts catalog shows 3:058, 3:06, and 3:07 !

Cheers
DD

 

Curiosity getting the better of me I looked up the XJ40 specs in the parts catalog

The ratios listed match the X300 ones I mentioned above....after a certain VIN (which I didn't make note of).

Earlier XJ40 shows 3.54 and later shows 3.58

<shrug>

Cheers
DD

 

I googled the part number for the crown and pinion and found this image:

I counted 43 teeth on the ring gear. A 12 gear pinion would be 3.583̅. 3.54 has to be wrong!

 

That must be the solution! A 43 tooth ring gear. 43/12. A 42 tooth ring gear gives exactly 3.50 which doesn't make sense to call 3.54. Impressive detective work! There should be multiple examples of this in YT diff rebuild videos to verify.