Help with diff identification please

[Spark]

Could anyone please help me identify a diff I have been given
The owner wasn’t sure what car it came off?
Any help please
Thanks in advance

[mgcjag]

68 is the year.....but better photos please......side on etc showing output shafts......is this to use in your E type. ...if so the mount brackets are important. ......E type bracket are a different angle to other models.....Steve

[mgcjag]

Ratio you can check by counting i/p turns to o/p turns....and check is it lsd

[Spark]

Thanks guys
See more pics
The input shaft for 4 revolutions turns the output shaft 1+ see pics starting and finish positions marked in chalk
The first diff shot from overhead is the end position and the bottom one is the starting position you can see the final position of the output shaft with chalk mark

Also pics of the output shafts

[mgcjag]

O/p shafts are the later type often refered to as type 3.....your diff ratio is 4+ something.......4.09 was a ratio used in 2.8 xj6 first out in 1968.....so thats possibly what its from......if you pull the rear cover off it will have the ratio on it......or calculate again and see if it works out to 4.09..........

[Spark]

Hi
Many thanks will remove cover and check for definite

Thanks

[mgcjag]

Ok just re read your diff turns info.......Lets go back a step....to calculate diff ratoi how many turns of input shaft to one turn of o/p shaft.....from your above info it wont be 4.09......also check if its a lsd as i mentioned above...Steve

[44DHR]

There is certainly something odd with this Diff !
The output shafts are definitely of the later type as the early differentials had a large nut holding the drive flanges on. I still can’t determine if this is a Type 2 or a Type 3 differential and also the “offside” outer bearing housing does not have the separate caliper mounting bracket - as seen on the “nearside” side. On the later differentials they had that caliper mounting brackets cast in the bearing housing.

I must admit I didn’t realise the number “68” identified the year the differential was built, but that makes sense. I have some diffs here with various “year” numbers stamped on which are all earlier dates than the cars registration dates they came from that I do know. Sometimes these dates are several years previously, but it still makes sense that that is the year of the differential build. I would be grateful if someone could positively confirm this “year” stamping as it will greatly help identify any differential.

As regards confirming the ratio, the only true way is to remove the cover as on the Crownwheel there are two numbers which give the number of Crownwheel teeth and the corresponding number of the matched Pinion teeth. Such numbers are 46/13 which gives a ratio of 3.54 : 1. The BP-L tag signifies a Powr-Lok Limited Slip differential which will become apparent as soon as you have the cover off as this is a large unit containing the various clutch plates. The easiest way is just to turn the outputs shafts which will turn in the same direction on a Limited slip differential as the shafts are normally locked together- as opposed to an “open” differential where one shaft will turn in the opposite direction to the other.

The other important part is not so much the differential itself - as many Jaguar differentials can be relatively easily still obtained - it is the inner fulcrum mounting brackets, as mentioned in post #2 these are unique to the E Type and very, very difficult - or very, very expensive to buy the re manufactured items now. I did contribute to post on these brackets previously:-

viewtopic.php?f=3&t=10004&start=20

Finally, the colour choice is unusual- almost military in colour.
Just my thoughts.
Regards,
Dave

[Gfhug]

Dave, my understanding is that the build year is shown on the diff case, certainly my three S2 diffs have had 69 stamped in.

Geoff

[44DHR]

Thanks Geoff for confirming this year date stamping in that location.
It makes perfect sense and I’m quite happy to admit in all the years I have worked on these differentials, I haven’t really taken much notice of them if I was stripping down the differential completely to work on it ! I am aware of the stamping of “C” in that location to identify the differential as the 2nd Type.
Regards,
Dave

[mgcjag]

Well spotted re the o/p shafts Dave.......one side has what looks like the type 3 seperate oil seal container that also mounts the caliper......the other side dosnt.......strangely exactly the same as this SC parts drawing thats put together just to show the different o/p shaft types......very odd.....Steve

[Gfhug]

I am aware of the stamping of “C” in that location to identify the differential as the 2nd Type.
Regards,
Dave

Are you sure about that Dave? I gave two S2 diffs to Alan Slawson to create one good 3.07 LSD. One was a 3.54 LSD with B on the case the other a 3.07 non LSD with I’m sure C. Alan told me the 3.54 B was the better case as he could get good bearings for them. Whereas for the later third type (C) the bearings were not as good.
Certainly my B case has the older style brake calliper attachment unlike the later third type that was on the 3.07 case. Not saying you’re wrong, just my interpretation is at odds with yours.

Cheers

Geoff

[mgcjag]

Hi Geoff.....the SC parts catalogue also mentions a C stamped on the "2nd type diff".....but iv seen a few diffs on S2 cars with the C stamp but the type 3 o/p shafts with seperate oil seal container......Steve

[Gfhug]

Thanks Steve, it looks like we are all correct I learn something new everyday on this forum.

Geoff