Gearbox Serial Numbers

Is there a list to tie a box to a car. I have recently bought a Moss box EB12156 JS, which appears to be a 3.8 shaved gear type gearbox but would like to know more of its background, ie what car and year. Does anyone know if this is possible?


If you ask very nicely I think Jag Heritage may be able to search by gb #… I know they can by engine number

Here are some notes I found in Dick Vandermeyden’s shop re: serial numbers on gearboxes…
3.8 gearbox serial number prefixes are EB with either JS or CR suffix which is for std or close ratio gears
4.2 gearbox serial no prefixes are KE (std) or KJ (close ratio) As of 1965 according to the research I did is when the gearbox changed to a fully synchromesh version. Could be at the same time the motor was revised or not? The production changes on the E-type were not coordinated like you might expect.
4.2 2+2 gearbox serial no prefix is EJS
Series 2
4.2 gearbox is KE (std) or KJ (close ratio) are the fully synchronized ones too.

Not quite correct.

Early 4.2 E-type OTS and FHC on introduction in Oct 1964 used EJ prefix gearboxes exclusively.
The 2+2 when introduced in March 1966 used EJS prefix gearboxes exclusively.
The xJ denoting standard ratio, but later in retrospect, are now considered Close-Ratio.

From about Oct 1967 onwards, the OTS and FHC got EE prefix gearboxes - the xE denoting 'Wide Ratio". 2+2 stayed with EJS.

From about March 1968 (so last of the Series 1-1/2), and for all Series 2 E-types the OTS/FHC gearbox was now KE prefix, and 2+2 now KJS, with Kx denoting a shallower-helix angle on gears for quieter running (and also absorb more power).

I am not aware of their ever being an EES nor a KES, nor a KJ albeit presumably possible to a ‘special order’


I have started a thread on the Forum trying to establish wherther or not my serial number KJS 2690 recently purchased gear box is close ratio or not. I have had various replies but non conclusive.

I note your post indicates that a KJ prefix is a CR box. The question is then, what would Dick Vandermeyden’s source be?

Jonathan Parker

1962 FHC 886918

Look at this website. Your box is a Series II 2+2 close ratio box.


The Jaguar Series 2 Parts List states:-1:


As I understand it, the KJS is specific to the 2+2, presumably because of the extension at the rear. This is, of course, for the full synchro gearbox, and not the Moss box fitted to the 3.8 Series 1s, which have a different naming convention. I usually don’t doubt the Jaguar Parts Lists, but they have been known to have errors…


Jonathan here’s the ratios for the boxes in question: EJ ( so called CR box) first gear to third - 4th is always 1:1
The ratios for the EE, KE, and KJS are 2.933/1.905/1.389. referred to as “standard ratio” originally and now “wide ratio”.
The original 2+2 box was the EJS with ratios of 3.04/1.97/1.33.


Thank you for that. It would appear then, if the S2 parts list is correct, that my box is a close ratio.

Although I understand that the CR box is much sought after, I am not sure that I prefer it over Std box which is a further question for me.



I have a close ratio gearbox in my 63 E also, from a 66 car that is.

I experience it extremely noisy.

Is that correct?

Not normal, no, but you should explain more about it and if the foam and/or jute underlay was left off during rebuild etc.

Which gears? Clutch status in neutral?