The 'E' Type Forum

in the process of ordering my new data plate I see that the original gearbox on my 3.8 was EB5225 JSO. Not sure I have ever seen JSO before. A quick Google came up with shaved gears? Anyway, out of interest can anyone put me right please?

Hi Andrew.

A quick dig into this, in Clausager's Factory-Original Jaguar E-Type he states:

'Gearbox numbers were common to all models and ran from EB 101 TO EB 15709. Gearbox numbers were usually suffixed JS (often JSO) for Jaguar shaved gears, rarely CR for close ratio ground gears; there may have been fewer than 100 cars originally fitted with CR gearboxes'

I have 3 books of Jaguar service bulletins from 1950 through to 1970, I'll try to remember to bring them to Bicester in April, there may be something more specific mentioned within them.

Best, Neil

excellent. thank you for that. In other words it doesn't sound like it was different to JS as such? Bicester here we come!

According to the nice chaps at Classic Jaguar USA the "O" in the JSO refers to the ratios

1st 3.375
2nd 1.982
3rd 1.367
4th 1:1

Too lazy to check that with standard but if it is different I never knew there were options on ratios .

Those are far wider ( in relation to 3rd and 2nd) than the E type standard ratios for the EB Moss box, which were 1.00 ; 1.283 ; 1.86 and 3.377 . I suspect that they are ratios more suited to one of the saloons . I did not think that they were ever offered on the E ( although ultimately on the 4.2 from about 1966/7 onwards, the KE and KJS boxes were quite similar to those ratios )

3.37, 1.86, 1.28, 1.0, - Moss box
3.23, 1.90, 1.39, 1.00, - Jaguar KP/KM
3.04, 1.97, 1.32, 1.00, - Jaguar EJS
2.93, 1.90, 1.39, 1.0, - Jaguar K* series box
2.68, 1.74, 1.27, 1.0, - Jaguar EJ series box

thank you David. Good intel.