VIN Plate question / identifying differential ratio

Just wondering, is there any identification of the differential ratio from the VIN plate / chassis number? Alternatively, is the ratio or an identifier marked on the diff casing itself? Our car is an automatic meaning the diff ratio is not recorded in the manual - I suspect it is the 3.77:1.

The Chassis Plate does not contain any information regarding the final drive ratio BUT, Jaguar did originally bolt a tag to the rear differential cover that documents the ring and pinion tooth count installed. Our '63 MK2 is equipped with a 3.8L engine and automatic transmission. The pinion count is 13, the ring gear count is 46. Dividing the ring gear tooth count by the pinion gear tooth count yields a final drive ratio of 3.54:1. Also worth noting, 3.8L equipped cars also came standard with a limited slip differential. Jaguar installed a second tag on the differential cover which contained “BP-L” when a Power-Lock differential was enclosed.

Before & after photos follow.


Excellent, thank you Brian - most helpful.

Hi Tigger
Just to confirm what Brian T has already explained
The 3,4 auto will have a standard 3.54 diff ratio
The 3.8 auto will have a standard 3.54 Powr Lok axle
The 3.4 manual overdrive will have a 3.77 ratio
The 3.8 manual overdrive will have a 3.77 Powr Lok
Hopefully, the diff tag is still on the diff cover bots
Brian UK

Superb, thanks Brian. Will investigate when next in those nether regions.

Another question about the VIN number.
I live in the Netherlands and have a from the USA an imported S type.
Can anyone tell me where to find the VIN numbers they are not at the crossbeam in front of the radiator as expected.
The only number I can find is the body number on a plate behind the rear bumper on the left side.
I hope that one of you can help me.

Did you check the VIN number using SALOON Data - The Cars - Jaguar, Daimler classic saloon (sedan) information, articles, photos and register
Could be that the cross member was replaced at some time.
A plate is not valid in the netherlands, it must be a stamped Vin Number.

You will find that the Vin is only stamped in the Bulkhead, as I mentioned before.

Peter Jan,
Thanks voor your replay and I checked all your tips.
As you stated perhaps the crossmember has been replaced in the past.
This week I ordered a certificate at Jaguar Heritage and this morning already received the digatel version of the certificate which shows that my S type has matching numbers. So another proof for me and eventually for the RDW that the car is as delivered in 1965.