Jaguar XjS transmission help.

[Krakenfelt]

Situation:
My 1990 XjS 3.6 auto is currently on axle stands being welded and fixed up. My transmission is slipping.
I ideally want it to be manual.

So my question is, what do I need to do a manual conversion, and out of 10, how much of a ball ache is it?

I’m considering the Getrag 265 route.
Do I have any cross over with parts from an Aj16 engine? For example the 269 gearbox?

Another important point to consider is I’m making this XjS a hypermiling touring car, so a very economical 5th or even 6th gear ratio is needed. Can individual gears be changed in gearboxes?

Thanks

[rougemont]

The manual conversion itself is straight forward, the problem you will have is that certain parts unique to the manual cars are getting hard to find at sensible prices, namely the adaptor plate between engine and gearbox, manual pedal box, propshaft yoke and manual ecu, although the car will run with the auto one. The days of finding a cheap manual donor car are long gone.
The 265 getrag was fitted to all 3.6, the later 4.0 litre and the AJ16 engined cars used the massive dual mass flywheel and 290 getrag , this can be fitted to the 3.6 but if you use the standard flywheel and clutch set up you will need to fit the earlier clutch fork.
The ZF auto box with the 4 th gear lock up is not a bad set up, especially compared to the 3 speed auto boxes fitted to earlier xk engine Jaguars,consider also that the auto cars are actualy slighty higher geared once in top than the manuals , so if lower engine revs at cruising speed are the goal fitting a v12 2.88 diff in place of the 3.54 would be a lot simpler, but dont expect to win any drag races.
There is an awful lot of excess weight in an xjs, reducing this along with an alloy rad and electric fans , de cat ( if fitted) and bypass the intermediate silencers plus a bit of igntion advance will probably give more gains than a manual conversion and cost a lot less!

[lukeharding]

I agree there is a huge amount of weight to be lost in an XJS but a manual gearbox does change the character of the car completely. No reason you couldn't do both, either. The manual 3.6 cars are surprisingly rapid, especially if you play with the suspension a bit too.

[Krakenfelt]

Thanks rougemont, lots of great tips. I’ve already fitted an alloy rad, centre silencer bypass pipes, and the Andy bracket. I’ve also taken out the AC, most if not all of the sound deadening. When you say decat, what do you mean, as I though it was the 4L that had cats? Can you think of any other areas weight loss can be found? I’m going to go for the diff swap too.

[lukeharding]

Krakenfelt said:

Thanks rougemont, lots of great tips. I’ve already fitted an alloy rad, centre silencer bypass pipes, and the Andy bracket. I’ve also taken out the AC, most if not all of the sound deadening. When you say decat, what do you mean, as I though it was the 4L that had cats? Can you think of any other areas weight loss can be found? I’m going to go for the diff swap too.

There is also a lot of sound deadening in the floor but its the sort of material you have to chip away at apparently, though it is quite thick. There is a lot of weight in the interior but stripping it out then becomes quite extreme. You also have the spare wheel which could be removed.