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     the TR O/D electrics is fairly basic. However the fault may not be electrical but you have to start somewhere.

To check the electrics - ignition on, select 4th gear and flip the column switch - was there a clunk from the O/D solenoid.
If yes  but the O/D still doesn;t work then either the solenoid is not positioned correctly and not rotating the arm far enough or the internal gubbins is dicky.

If the solenoid did not go clunk then apply 12v directly to the solenoid - if it doesn't go clunk then the solenoid is dicky.
If it did go clunk then the wiring from column switch to inhibit switches are dicky.

On the righthand side of the gear box there is a lever that rotates with the solenoid action. This has an alignment hole that needs to be set correctly.


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Access is not good from below. Some cars have a hole in the tunnel next to the solenoid (if the PO put one in) and just needs the pax seat and carpet removing.

Any of the cheap digital meters will do for what you want. Gunson do some good cheap models (halfords etc).
The red positive lead goes into the red socket on the meter and black goes to black.
Rotate the switch to Volts DC it may have a symbol of a V with a straight line next to it with a dotted line beneath it.  AC has a wavy line.
Switch to a Voltage range immediately above 12V - eg 20V.
Place the black lead on the chassis or negavtive pole of the battery. Place the red lead on the wire/tag your testing - if live you should have 12volts.

12volts is nominal for the car it may be higher (13.7 ish) or lower depending on the fault.
Try it on the battery first to get an understanding.

I see in your picture that there is an uninsulated connector hanging around.
This may not be a good idea on the O/D as  a lot of it works by making the earth conection and your connector may make earth at the wrong time.

You should have a J type O/D with no relay for the solenoid so checking the wiring should be fairly straight foward

If you haven't got a wiring diagram check this out



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Another thing to watch out for is a blocked filter in the overdrive pump, this can be removed by taking the O/D cover off, clean the first filter, then under one of the three socket type covers (use a set of pointed pliers to remove) is a nother filter that is probably quite full of crud, this also stops the overdrive working, It should be cleaned occasionally anyway. I would suggest ordering a new gasket before you disturb it! If the unit does come to life, fit the uprated over drive vlalve that chris wittor (and maybe other?) sells it makes a huge difference to the engagement of the overdrive, especially if it is putting out higher than normal amounts of torque.

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Good point about the filter. Whilst in that area I take it that you have checked to see that you have enough oil in the gearbox.

What oil do you use (if any!!) It would appear that if it has any association with oil then it has been used over the years - gear oil, diff oil, engine oil + all the various grades.

I believe in using gear oil in gear boxes and use Penrite SAE 40 - works well, but then do all the others (usually)


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okay, reversing lights do work fine. I managed to get the voltmeter on to the switches. i have power to the swicth on the left, but nothing for the one on top of the gear box and nothing at the solonoid either.

where does the switch at the top get its power from, work back: the solodoid, and then the solonoid is powered by the switch the left? so would that mean the solonoid is caput?

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clean filter top up oil then with rear wheel off ground start engine put in third and put a live direct to solonoid(do not do this in reverse!!!!!!!!)make shore the car is properly suported no need to use excess engine rev and if it works   the prop speed will increase regards michael

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