Here is my solution....I made two half brackets with a lever to clamp around throttle linkage. Have just made a mounting bracket to hold a microswitch. The idea being that when accelerator is to the floor, the lever rotates, activates the microswitch and the BW12 trans will kick down. thats the theory!!! Just have to mount, wire and find the 12v lug on the transmission that activates the kickdown. Hopefully the theory works!!

 

What does this switch actually switch on the Model 8 gear box?

 

I thought this was a BW Model 12 Transmission?

Model 12 as used in Jaguar XJ12 and Daimler Double Six Series I-III (1972-1992).

 

Just read back on the other post and you are right Model 12.
Same question though what does the switch operate inside the gearbox to make it kickdown?

 

As I said on the other thread ~ who knows??? There is likely some over rev protection built in somewhere.

This is as much as I know about the BW Model 12

 

I think very early XJ6 had Model 8 (with kickdown cable). From 1970 was model 12 (mine is from S1 XJ6). I found the 12v tab for the kickdown solenoid on the gearbox so its a Model 12.

 

Yep Glyn - thats it!! Thx

 

The Model 8 was first fitted to the 420 & late MkX 4.2 in 1966 before it became a 420G. The BW35 could not take the torque of the 4.2 engine.

 

OK so that explains it then. Inside the gearbox there is a solenoid just as there is on an over drive unit and when the switch is hit the solenoid changes down a gear. This then takes me back to my thought that at high speed if you hit the switch you are likely going to set off the solenoid and have the gear box change down to a lower gear unless there is somewhere in the system an override that stops this from happening. I think I would prefer a manual switch on the dash or on a column stalk rather than under the throttle pedal. I mean how many times in a journey are you going to need to kick down a gear.

 

I can find very little written about this transmission but do note that it has a mechanical governor which I suspect would inhibit a change down at high RPM to protect the engine from an over rev situation & ignore the kick down in that case.