Overdrive?

[Hugo]

Is it possible to fit an overdrive box to a Series 2 Roadster? I would prefer that to a 5 speed, but if it won't fit.......

[Heuer]

No, it won't fit. You can use a Jaguar MOD (manual with overdrive) to replace the auto box on the 2+2 though.

[iani]

Jaguar MOD from S-type or XJ6 can replace any 2+2 'box, not the MOD from a MK2 though as the rear extension is too long.

Ian

[abowie]

To decrease revs at motorway speed your options include:

1. Fit a new 5 speed box designed for the car. Best one is the JT5 from the US. There are other options too. Cost is big $$$$

2. Change your diff.
If you currently have a 3.54 diff, you will find a 3.07 a big improvement.
If you currently have a 3.07 you can go to a 2.88 from an XJS. This will make racing starts in first gear a little awkward but the 4.2 engine has bags of torque and will otherwise cope well. Cost is $$ in comparison to the 5 speed box but you will have to rejig your speedo and odometer.

I have a 3.8 with a 3.54 diff and a JT5 box. It's brilliant. Fast off the line and 2200 rpm at 70mph.

I also have a 4.2 with a standard 4 synchro box and a 3.07 diff. It's just as good but 2900 rpm at 70mph.

It all depends on how you drive your car. Me? I drive it on windy 50mph and 60mph roads through the hills, and not so much on the motorway.