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TR2/3/3A overdrive does not function

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Hey thanks Hamish for your input my engine is stock. If I wind the engine up in 2nd OD and then shift to 3rd--- I assume the 3rd is going to be 3rd in OD. -----So, now can I switch down to non-OD 3rd and winded up the engine again and then shift into 3rd OD. Will that cause problems with OD because of the snapping up and down of OD.

Steve
 
It won't hurt the OD do use it frequently, but if you do, you may want to incorporate Randall's suggested diode to the relay. The diode will kill the voltage spike from the solenoid when disengaging the OD, and keep from burning the relay contacts. A search will bring up several threads Randall described how to install the diode.

In answer to question above, "yes", if you are in OD 2nd and shift to 3rd, you will end up in OD 3rd. But...the OD will actually cycle during the shift. In other words, as you move the shifter through neutral, the switches will cut out the OD, and then re-engage it as the 3rd switch makes contact. While that is not bad, it needlessly cycles the OD.

OD is mostly for mileage in 4th gear. That said, the racers learned to use it as "extra" gears. That is why it was originally only switched to work in 4th gear (mileage), but later switched to work in 2, 3 and 4th gears. To use it as extra gears, you would start in 1st straight. Then shift to 2nd, and then 2nd OD. Next, shift to 3rd while clicking off the OD, so you go to straight 3rd...and then OD 3rd. Same to 4th. Click the OD off as you shift to 4th and go into 4th straight...and finally to 4th OD.

Personally, I don't need that many gears, as the Triumph engine is plenty torquey to work through the straight gears, and then add 4th OD to get better mileage and less engine whine on the freeway. You can use the OD anytime...uphill, downhill, etc. It will not hurt the OD.
 
sp53 said:
Ok I think I am seeing things a little clearer. The remote start is not going to work because it does not stay on and there is a chance my other switch will work if the switch stays closed. Has anyone taken apart an original switch? They are interesting inside with a spring in the middle between two poles with a brass plate that slides back and forth between the poles. I just cannot see how to make mine work. It is like the switch needs a 3rd wire or something. I really would like to fix this one.

Sounds like I need to get a new switch before I can do much testing. I could use a house hood light switch to see if the solenoid does its job and I guess there is an adjustment on the solenoid also; heck i am not sure if it works yet. I appreciate all the help, I think there is smoke coming out my ears.



steve
Click to expand...
Steve, I had a problem with the OD switch sticking so dismantled, cleaned out gunk, and reassembled with a thin coating of dielectric grease. I have a picture of the insides after that was done. The spring provides an over-center mechanism to assure quick, positive contact with no 'bouncing' of the contact.

Jeff
 

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Hey thanks you guys. I do need to drive this car more and John thanks for the heads up on the OD. Tropic 6 do you remember how the wires fit in the switch? It looks like the center position is for off, and top and bottom are on. BUT it looks like there are 3 places to put the wires? The original switch I have looks just like yours. Now I think mine might work again.

steve
 
sp53 said:
Hey thanks you guys. I do need to drive this car more and John thanks for the heads up on the OD. Tropic 6 do you remember how the wires fit in the switch? It looks like the center position is for off, and top and bottom are on. BUT it looks like there are 3 places to put the wires? The original switch I have looks just like yours. Now I think mine might work again.

steve
Click to expand...
Steve, Internals of that type were also used on dash headlight 'Main - Dip' switches on some cars (MG TC/TD for one). All 3 terminals were needed for that, but only 2 are used for an overdrive set-up. The center terminal connects to the relay ground, one other terminal goes to the gearbox cover switch(es), and one terminal is not used. When connected it provides a ground to close the relay contacts to power the solenoid - as long as a cover switch is closed. I can get a picture in a week when I can get to my stored pictures.

Jeff
 
Thanks Jeff I think my switch is hooked up wrong and a picture would help. I do not remember a ground on the relay. Would that be a case ground? I do remember some switches using a ground to complete a circuit somewhere; I think it was some wipers or something.
 
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