TR6 A type over drive stopped working

[vantager]

Bought a 1970 TR6 last spring and the overdrive has stopped working.
When I have the ignition on (car is statonary, engine not running, in 4th gear) and flick the overdrive stalk on/off I cant hear the solenoid click.
From what I've read on the internet, I should be able to - anyone disagree please?

[silentbrown]

A type has a relay too?

You should be able to check if the relay's working correctly, which would rule out the stick switch and the gearbox inhibitor switch.

[vantager]

Sorry to sound dumb but where is that and how do I check it?

[Hawkshaw]

IIRC, the relay position varies on different versions of the car but is likely to be somewhere near the fuse box. It is a rectangular tin can with 4 terminals.

Keeping it simple - Ignition on, engage third gear, switch overdrive on, and the relay should click. Repeat in fourth gear.

If it doesn't click, you will need a multimeter or test lamp to get any further, A lamp will do fine, e.g. a sidelamp bulb in holder with two insulated wires attached. Connect one wire to a good earth point, touch other wire to terminal being tested.


On the relay, brown wire to terminal C1 should be permanently live. White wire to W1 should only be live with ignition on. If not, check fuses and connections at fuse box. Then with ignition on, connect a test lead between W2 and earth, and relay should click. C2 yellow/purple should then be live. If so, relay is okay.

If the relay checks out, then the suspects are 1. the overdrive switch, and 2. the wiring to the gearbox - connections to solenoid and interlock switches. Note black wire B at lower right of diagram, which must be a good earth connection to the body/chassis.

Only if all that checks out do we suspect the solenoid. Most electrical problems are caused by bad connections and bad earths.

Have I lost you yet?

[vantager]

Thanks very much for such a detailed reply