The catch as i understand is governing when the converter is locked and when it is “loose”.
Definitely, want it loose at a stop with engine idling. In my app, not same as here, the brake pedal actuates a witch and opens the lock circuit.
Advantage, is locked at normal and above speed. No converter slip. efficient!!!
Car is more responsive to throttle with converter locked.
Some say that if the slip is allowed, the transmission will fail… others, not…
Carl
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It’s supposed to be self contained and automatic, Eric - basically locking and unlocking to protect the box/engine from ‘something’…
The switch mentioned by Robert seems to be a useful feature to override that ‘something’ - it would be interesting to know how, and to what, that switch is connected. Or indeed if his switch is a necessity to counter some failure of the box to operate as it should…?
Frank
xj 85 Sov Europe (UK/NZ)
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This is also my understanding: under normal conditions, the lock up solenoid is activated/turned off at the right time by the right pressure in the 4th gear valve mechanism. It can also be wired to allow for an external switch to be controlled manually or another engine organ.
I chose to go simple for now and to bypass the switch option by shunting the wiring as recommended by various pros providing advice on youtube.
Thank you for posting those pics Eric, please do be careful. 
The travel requirements for the TV cable are very specific and the resulting mishaps are what give the transmission a bad name.
Thank you for this. At the moment, with a rough fit of the little extension I rigged, the TV cable is taut on zero throttle and fully pulled out on 100% throttle. I suspect I am not too far from where I should be… 
So the time has come to direct attention to the driveshaft.
The kit I bought came out of a S2 saloon. So the driveshaft needs to be shortened. I have measured the distance between the cone nose on the THM and the diff yoke flange at 49 1/4 inches. I will bring this to the driveshaft shop and let them work out their magic. The shortening will have to take on the front part of the shaft (large diameter) as the rear support plate fits exactly where the support platre should be on the underside (relief).
The UJs seem in excellent condition, the big rubber bearing on the rear support plate however seems to have seen better days.
My workshop mate is pushing to get a new aluminum one-piece shaft instead of getting this 2 parts item rebuilt. Any wisdom here?
Hi Eric,
Did this conversion 2 years ago. I did have the front section of the driveshaft shortened and the GM yoke welded on. The shop I used could not balance a 2 piece shaft (as they said the whole shaft has to be balanced as a unit) so sent it out to another shop that could. The most they could get up to while balancing was 750 RPM. The car runs vibration free on the highway, on decel also. Might want to check if there is a shop around you willing to balance the assembly. I know John('s cars) says a one piece shaft will work just as well, so the choice appears to be open.
My lump kit came via Johns cars. A one piece steel shaft of the right length included. It works just fine. Simple is good…
Carl
Local driveshaft shop wants to see the beast in the flesh before advising on chosen route.
A shaft that connects the transmission all the way to the differential, or just to replace the first half of the Jaguar two-piece shaft?
So I will go with a new one piece drive shaft.
But I just discovered that I need to bang a dent in the transmission tunnel to get the transmission to fit… Damn.
I had to bang in the transmission tunnel a bit on the right side to get the transmission to clear (this is in the instructions that i neglected to read…).
Also drilled two holes in the tunnel to tie the adaptor plate to the floor, the adaptor plates bolts onto the transmission rubber mount and the Jaguar driveshaft plate.
Then fitted the drive shaft.
All seems to fall in place (may need to trim the tunnel a little more to avoid contact with the very rear if the transmission sump.
Now I will have to take it all apart to fit the gear lever cable to figure out what is going on with the speedo cable (the oem one is clearly too short).
I remember wishing I’d hammered the tunnel a bit more.
As the engine tilts under load, it touched. It’s tight.
I remember there were 2 types of hard rubber trans mounts, of slightly different thicknesses, to obtain best clearance. I can’t remember which I used, but there are choices.s
Good luck,
Rob
Hey there,
Have you seen this thread over on the other forum?
https://www.jaguarforums.com/forum/xjs-x27-32/700r4-quarterbreed-conversion-johns-cars-234770/page5/
its for an xls conversion which is very different, but there is some useful information.
best
carl
Now that everything is fitted, it is clear that I still need to make more room…
Eric how is your trans conversion coming? Sorry to make a post and not come back for 6 months. I have a few other projects that demand my time and hopefully they will be finished soon and I can get back to my XJc, E-type and Tr6.
I didn’t realize your car was carbureted (no throttle body) as my 86 has fuel injection and was speaking from my project. The TV cable geometry will still be imperative and will relate to your carb throttle shaft position. Be aware that just because the length of the inner cable seems correct and adjusts out, all may not be well. Do study the bowtie overdrives article on TV cable geometry. I bought the one piece driveshaft from John with the kit and it was all a very enjoyable experience to fit everything, I also removed the inspection plate at the back of the cylinder head and addressed all concerns there while I had easy access. I have pics of the TV cable mod and adapter somewhere, if I can find them I’ll post here.
Coming together slowly.
Here is the little adapter I fabricated to fit the TV in place of the original cable.
The engine is now starting and running.
Soon I will attempt to move the car under it’s own power and i am starting to look at the les essential organs, like… the speedometer.
The box of parts I have contains what seems to be a SIII transducer which i suspect I could hook to a SIII speedometer. I however suspect that this will not show the right speed, even less so if I replace the differential for a lower ratio as the THM700 would allow me to do.
I wonder if there are more modern options (GPS speedo?) or techniques to calibrate the SIII speedometer.
Thanks
I never worked out the transducer on mine for the Speedo. Instead since the car is already custom I got a gps Speedo.
