Yes that is certainly possible. Then I wonder where the longtail OD came from. It came from an SA built car we were told. Probably changed in local production when we started building the 3.8 S Type in January 1966.

I wish someone would photograph the underside of their MOD 340 on a hoist.

My car was registered before it was built which is why I call it a '65. It was built Jan '66 & QCed by Lyons himself to ensure up to Jaguar standards. I have never got to the bottom of that one. It was the 4th S Type built at CDA East London. Today demolished & replaced with our State of the Art Mercedes Benz plant.

 

I know some of the history of the one in the picture that I attached. It came out of a 240, a rebuild that was abandoned when the owner decided the corrosion was too much for him to repair. It has KCN on the side making it definitely a 240 gearbox. I'm fairly confident that it is what it's supposed to be - sufficient that I bought it.

There's some confusion in the literature from various authors and the factory in that they often indicate the all synch 2.4 to have the same ratios as the larger engined cars. However, the KCN ratios are different from the JCN.

 

Correct: And Moss gearboxes had a lower ratio first gear. Jaguar where never going to satisfy everybody. I like the ratios on my 3.8S.

 

The KCN has (or should have according to the literature) the same ratios as the close ratio versions of the all synch that was optional on E types and the S type.

 

So what it boils down to is that the S Type had to have 2 different length propshafts for MOD whereas the Mk2 not. (SA production excluded). The Moss box was never fitted with the compact OD.

 

What we can say for sure is that the Mk2 and S type MOD had different lengths bell face to rear flange and different length prop shafts to compensate.

Did you check if the change in part number for the S type prop shaft coincided with the adoption of the 4 synch gearbox? The Mk2 had a change in part number for the prop shaft but it doesn't coincide.

 

It seems to coincide as best I can gather.

 

https://www.ebay.co.uk/itm/386251794...4089&recoPos=1

This looks like a genuine 340 all synchro MOD. It's not a bad price, though a lot more than mine. I've bought from this supplier before and they seem to be OK. It has a strange paint job - I thought they were black or bare metal.

 

Ah! Interesting. It has the compact OD but long tailshaft. Have you ever seen a Moss GB with the compact OD fitted? As I say above I have not.

 

I don't believe there ever was one. One might ask what the motivation was for the switch?

 

OK so only S Type has 2 different length propshafts. The 420 would never have been fitted with a long tail Moss MOD.

Motivation ~ To shrink the tunnel???

 

The new front seating arrangement is quite different in the S Type. The floorpan is quite different to a Mk2 right down to mounting points. It is subtle at a quick glance but actually different. Jon Skinner got caught out with the underfelt & carpets S Type vs Mk2. Now long corrected.

 

Refresh page for edit.

 

Hey Peter, thanks for that.
The car's in California... wouldn't dare take it down to CR, not the place for it.

I think I will contact Ken in the UK, sounds like the best bet...the Moss is ok...I can double-clutch with the best of them...but since it appears it's all coming out, I'd rather just go with the later setup, as even after shipping I reckon it's still cheaper then going the with the Tremec 5-speed setup.

 

Thanks Glyn, this is the way to go for my needs....a 5 - speed is to pricey and just not needed imo.

 

And it get's you away from the non synchro howling first gear of the Moss gearbox. I can't stand the straight cut vintage gear howl of the first gear of the Moss. The Moss is at best somewhat agricultural.

 

In the Words of James Taylor ~ "Replacement for the old Moss gearbox was really long overdue. For the gearbox, there were the beginnings of a complete change, from the sturdy old Moss four-speeder with its unsynchronised first gear to the brand-new four-speed type designed and built by Jaguar themselves. However, the Moss gearbox was, frankly, old-fashioned and was not at all suitable for a car of the S-type’s pretensions, let alone those of the Mk X in which it was also available. Perhaps customers who bought the S-type as a small luxury saloon usually chose the automatic option, but there was no doubting the need for that new gearbox.

Full production began in March 1965. As before, overdrive was an optional extra, and there was a new type for the 1965-model S-types, although it was supplied by the same maker who had built overdrives for the earlier cars. Its key features were baulk-ring synchromesh on all forward gears, and provision for a pressure oil feed. This was achieved by a pump driven from the rear of the mainshaft unless the gearbox was accompanied by an overdrive, when the overdrive oil pump also fed the main gearbox. From the driver’s point of view, the all-synchromesh gearbox was a very great improvement, offering a smoother shift action and quieter acceleration away from rest – although some enthusiasts must have bemoaned the loss of the vintage whine emitted by the first gear in the Moss gearbox. Revised gears in the new all-synchromesh gearbox also made a perceptible difference to acceleration in the intermediate ratios. Despite these advances, the Jaguar gearbox still has its detractors more than fifty years after its introduction. They argue that the higher first gear takes the edge off initial acceleration; that the gear-lever travel is longer than on the Moss gearbox and so hinders quick changes; and that the newer gearbox lacks the character of the older one. So be it: Jaguar probably knew at the time that they would never be able to satisfy everybody when they introduced major new components."

 

Refresh page ~ cleaned up duplicated comments. I did a poor cut & paste job at 4am in the morning our time.

 

Chris
You are on the right track to go for a late model full synchro overdrive box.
Somewhere in the past somebody fitted this sort of gearbox in my 1960 M2 2.4 and it is a gem to use after many years of handling moss boxes (I started in 1964)
If I get nostalgic, I can always take my MK1 for a run as it still has the moss box.
You will have to replace the gearstick knob as reverse is hard left and rearwards as opposed to the moss box's hard left and forward.

 

In the words of well known journalist of Autosport, John Bolster, in his Road Test "The gears are easy to change, have crash-proof synchromesh on all four speeds, and are controlled by a delightful little lever."

This is the change in gear pattern that Bill is talking about plus Knob