Definitely not original. it appears to be an improvised electrical `kick-down´ to replace the mechanical kick-down which would normally be operated from a linkage (push-rod / bell-crank / sprung connector rod) by the rear carburettor. The mechanical kick-down operates at wide-open throttle settimng, and over-rides the hand-setting of the intermediate-hold control forcing the box straight into Intermediate, until the throttle is released when the box goes back into top. Check if the switch is operated (and closed) at wide throttle opening. If this is the case then it is almost certainly a home-made kick-down. This should energize the solenoid, which should then activate the small ´Intermediate-hold´ lever at the back of the gearbox. This would change from top to intermediate range, and back to top when the throttle was released / closed, in theory. If there is a solenoid (with push - pull rod) for kick-down this may also be improvised. I don't know if B-W supplied these as standard, but I think it is unlikely they were ever on a TD21. Originally there is a long, spring-tensioned rod with a ball joint attached to the small gearbox intermediate-hold lever and to a small bell-crank linkage by the rear carb / manifold. Could be the manual Intermediate-hold setting cable is disconnected or totally missing, and the improvised solenoid is the only means of putting the box into intermediate above 30 mph. Best way to find out is as already suggested: Try it out! Energize the solenoid before the throttle reaches the switch (just join the wires together to bypass the switch) and see if the box stays in intermediate. Then Disconnect the switch totally and see if the box goes straight into top at approx. 30 mph. Hope this helps, Giles Lacey Posted by lacey giles 24/01/2013 18:37:32
