Richmond ROD Transmission installed in a Jaguar XJS
After doing a lot of modifications over the years to my 1983 XJS, about the only thing left was to go with a manual transmission. I had installed the Tremec kit for a customer and driven a few others including the Getrag and other Tremecs. I was not overly impressed with the shifting or feel. The stock Jaguar 4 speed in the XKE is a real nice transmission and seemed to be a bench mark from which to compare. One day a friend called with an offer I could not refuse. Seems he had a customer who had paid him to put in a Grand Tourismo 6 speed kit in his XJS. The story was that he hurt his back and could not shift comfortably any more and wanted to go back to an automatic. Would I be interested in supplying the automatic and pieces needed to convert back in trade. Needless to say, I ended up with the transmission and related parts.
The original kit came with a lightened tapered aluminum flywheel and a double disc clutch 7" in diameter. The whole assembly only weighed 15 pounds. The engine sounded like a race car. For what it sounded like, click HERE. The clutch was either on or off and a real bear to push in. It was almost impossible to drive in traffic and smooth starts were a thing of the past. I ended up going to a stock aluminum flywheel with a CenterForce clutch and pressure plate. This assembly weighed in at 35 pounds which was still about half of the Auto Transmission flywheel and torque converter. This smoothed out the engine and made the car rather docile around town.
This is kind of getting the car before the horse though. Putting the transmission in the car was the first order of business. The transmission has external linkages on the left side. There is not room to fit it into an XJS without some modifications. I ended up cutting the left side of the tunnel out, putting the transmission into place and building a aluminum plate to cover it back up. Then insulate and put back together. The picture is below. BTW: click on any picture and you will get a larger image. The Pilot bushing is nothing more than a stock Jaguar bushing with the inside cut out to the correct diameter. The Release bearing assembly and clutch came from Walt Osborne.
Once the transmission was in the car and mounted, it was time to make the shifter come out in the correct position. I made a dog leg piece of metal so that the shifter would come out in the correct place. The rubber shift boot was what came in the kit but I did not like the looks of it so I used it to seal out heat and noise and went with a shift boot from Robert Hall at "The Driven Man" Pictures below show how I mounted it up. I found that gluing it in place with epoxy worked very well. Threading the plate to hold the screws to hold them in place also helped.
The clutch pedal box came with the kit but as Jaguar made the XJS in six cylinder form, the parts are available out of scrap yards but most likely in England. Once the pedal kit was installed, it seems that the clutch pedal was about an inch higher than the brake pedal. I ended up making a spacer to mount under the master cylinder to bring the pedal down. This in turn necessitated modifying the hood to clear the top of the master cylinder.
All in all, the conversion transformed the car. The gearbox is a nice shifting transmission but a bit cold natured. I have not been able to beat the gears as it can be easily speed shifted. The V12 has enough torque to pull from 1000 RPM's on 6th gear and start off in second on flat surfaces. The gears are more of a straight cut design so a bit more noisy than the Tremec. 5th is direct so it is silent and by the time you are in 6th, road noise drowns out the slight whine.
The interior of the car appears stock except for the shifter and pedals. I did not hook the cruise control but it certainly could be if desired, I just never used it so did not bother. The ECU modification is a must. The stock ECU cuts off the injectors above 1200 RPM's with the throttle closed. If you are decelerating in gear and pop it into neutral, the engine drops and with a light flywheel, the speed drops so fast that it has stalled out before the injectors come back on. Due to the nature of an automatic, you don't shift into neutral coming up to a stop so this is more of an emmision and economy design. Having this circuit will fix this condition. Roger Bywater at AJ6 in England performs this modification. If you go with a heavy steel flywheel, you might not experience this problem but then why would you bother going to a manual if you are not going for performance? I hope this article helps, write me if you have any questions Dick Maury