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Triumph TR6 - overdrive lever position...

Gentle Geese,

My 73 has overdrive. The overdrive is not "hooked up" electrically as there is no solenoid on the unit.

In which position does the overdrive engage? When the lever on the od unit is up or down?

Will it work merely by moving the lever mechanically?

I understand about not using od in reverse or first gears and the disasterous consequences of doing so.

Is the od unit currently UNENGAGED? I'm thinking it must be as I've driven the car for some while and haven't hurt anything yet.

Can one test this od unit by pulling up (I think it would be up) on the lever whilst dumping the clutch in 4th?

Inquiring minds want to know.

As always, thank you in advance you wealth's of knowledge.

Jim Deatsch

Hi Jim
The OD lever is on the left side of my steering column and overdrive is engaged when the lever is in the up position.
If you have no solenoid the OD is permanently disengaged.
Basically a live wire goes through the column switch, to the inhibitor switch[s] on the gearbox and then through the solenoid to earth.
May your goose be with you always.
R. Algie

Jim, My '72 has od and the switch arm is on the left side of the wheel. OD is engaged by dropping it down, it will work either by clutching (my prefered method) or dumping (in gear drop lever and go). But Ron is right I think a solenoid is required for use.
Regards, Keith
Keith Dixon

Also the solenoid is located at the left side of my car just aft of the fuse box, the original one had a 5 male plug setup my new replacement from lbc has a 4 plug which is OK as I have 4 wires to stick in.
Keith Dixon

I didn't make myself clear.

I have no switch. I have no solenoid.

I believe, as Ron said, that the OD is not enabled unless the solenoid is lifting the LEVER ON THE TRANSMISSION.

My question is, why would one need anything OTHER than to lift the mechanical lever on the transmission?

The switches on the trans are merely there to pass electricity IF you are determined to NOT be in first or reverse gears, or so I've been lead to believe.


Jim Deatsch

After reading your first post I thought it funny the responses. I guess normal people do not put their hands through the gear box cover and move a switch:) But for you I will answer. I am not sure if you are an A type or J type. It sounds like A type. Yes the solenoid, when attached, pulls the lever up. The primary winding of the solenoid does the "pull" the secondary coil winding does the "hold" so you decide who is going to do the "hold":)
The opposite side of the tranny to the lever has another lever that is attached to the operating valve. You will notice that this other lever( passenger side) has a hole in it and there is also a hole in the tranny casing. When these 2 holes are aligned this is the correct position for the "hold" of the solenoid or in your case your wifes hand. Lets face it, you need 2 hands to drive and change gears:)

DO NOT put a rod in there to hold the lever in position. You might regret doing this.

The switches on the tranny case are to prevent power to the solenoid in the event the overdrive switch ( normally located as stated above) is left in the one position. A safety feature if you wish.

Keith, me thinks you are refering to the relay not the solenoid. I also prefer to clutch but then there are others who do not.

Rick C

Rick Crawford

Sorry Jim you're post is clear, I read what I thought was there and not what you had actually written.
Interesting that that Keith's OD column switch works the opposite way from mine, I wonder which way they were originally?
R. Algie

So Rick, if the hole were in alignment and the lever were up then I'd be good to go or can I still not engage the OD mechanically?

Is there some pressure issue involved here or is it purely mechanical?

I'm not clear (go ahead, <G>) on what else would determine whether the OD engages.

Ron, I'd wager it's supposed to be UP to engage the OD. After ALL, that would make sense, up to faster at lower revs. Oh wait, 'make sense'. I just answered it. It would be down then, unless that's how they WANTED us to think, then it would be up.

I'll consult the goose.

Thanks guys,

Jim Deatsch

My '71 DPO modified the OD switch. I think he broke it off and then re-attached the stub and reversed the switch (?). It now operates like the headlight switch (down=on).

I need to adjust/rebuild the solenoid as my OD will only engage occasionally! At least I hope the trouble's not deeper in the OD.

EC Smith


Before you have a go at the solenoid I would consider adding a relay in the switching circuit. The problem of an intermittend functioning might well be a low voltage at the solenoid terminals caused by voltage drop through the circuit.

Erik Creyghton

hahaha I think Erik means Jim..not Charlie
Charlie Ballard

Charlie? You mean we've got TWO Charlies now?


I'd better tell the goose.

Jim Deatsch

I recall my brother having a Healey 100 M or S that had a manually operated OD on the backward 3 speed, was connected directly by cable & lever to the OD. Worked fine!
ED Edward Dorsch

Yes if holes alligned you are "in spec" for the correct position of the operating valve. The 2 levers ( solenoid, driver side, and the valve lever, passanger side, are mechanically the same lever. I suppose the 2 holes are a visual means of setting the valve to the correct operating position. You see that the solenoid is adjustable as to is amount of pull. This amount of pull must also be correct so that when the OD switch engages the solenoid the solenoid internal plunger (surrounded by 2 magnetic coils) pulls up high enough to engage a contact at the top internal hole (where the plunger slides up and down). This little contact shuts down the primary winding (pull.... high current draw) and engages the secondary windings ( hold...low current draw). This adjustment is critical. If the secondary winding is not engaged then the solenoid holds the lever up using the primary winding high current coil. This will cause " melt down" of the solenoid.

There is no pressure involved here at least not mechanically to hold the lever up. There is hydraulic pressure internally in the OD. A valve is opened and oil pressure activates the OD...trying to not get carried away here.

"I'm not clear (go ahead, <G>) on what else would determine whether the OD engages."

Jim, there really is nothing else to determine if the OD engages or not In your "manually operated" situation. In your situation, while in 3rd gear say, pull up on the lever (try to determine how much ahead of time by looking at the 2 hole allignment) and you should hear it engage and RPM will drop.
In a "normal" situation preventers from making the OD work could be, wiring, relay, solenoid, low oil, incorrect adjustment to solenoid, no voltage.... I could go on.

NOTE: '71 an older had the relay...'72 on had no relay.

Charlie (EC SMITH) The solenoid is wide open to the elements and has a rubber boot on it but you know what happens to rubber over time. It could very well be that your solenoid needs a good clean. There could be rust inside. As said the plunger rides up and down inside the "barrel" of the solenoid which is a glorified magnet. If removed from the OD the solenoid can be cleaned out. Remember, there is a contact at top of the barrel for secondary winding "activation".
Also oil level should always be correct in the tranny....the tranny an OD share the same oil. I covered my plunger with DG.

Rick C
Rick Crawford

Jim et. al.--All your answers are at the Buckeye site; especially Section 3 of

Rick O.
Rick Orthen

Rick and Rick,

MANY thanks for the replies guys.

Now I have to READ again. Sighs. All this work, still haven't driven the car this year. <G>

Really, thanks,

Jim Deatsch

Thanks here too!
EC Smith

Everything I'm finding now indicates the switch should be in the UP position to be in OverDrive.

hth EC,

Jim Deatsch

When you walk into a room and flip on the light, you click the switch up. The overdrive switch on my TR3A is like that.

Don Elliott, 1958 TR3A
Don Elliott

Gentlemen, and Ladies,
If I may offer a couple of observations on this topic.
The operational position of the switch is as some have pointed out, UP for OD operation, and DOWN for NON-OD.
The differences that some have reported, ie switch operating in reverse (DOWN for OD on), stems from the fact that the switch supplied at some time after the production of the car, such as a replacing a bad switch or installing an OD where none has been previously.
The switch that was supplied to me for my OD conversion, was wired such that when installed in the car it would operate in reverse ( UP-OD off, and DOWN-OD on). This is easily changed as the switch is a two position switch, in other words it closes a "circuit" in either position. There are three terminals where the wires connect to it. One is common, and the other two are "operational" in one or the other of the switch positions. If your switch is working in reverse, all that needs to be done to change it, is to reposition the wire connected to one of the outer terminals, to the unoccupied outer terminal. This will merely cause the OD circuit to be MADE, when the switch is in the Opposing "STATE".
Apparently this switch has served many different functions form LBC's in the past, and I am not saying it is correct for this application, but it is "probably" a supersesion part number, and as a result, is now the only one available from Lucas.
It can be a PAIN to get to, in order to move the wire from one from one terminal to the other, but it can be changed. This does require Soldering skills, and you have to be careful not to overheat the switch "bakelite".
Sorry for going on so long, but I hope this will clear up the mystery, and maybe help someone get their switch to Whatever position they feel it needs to be, UP or DOWN.
That brings another thought, Maybe you "mates" downunder want your switch to work oposite of the ones in the northern hemisphere?
Sorry, I was only kidding. Where ever A TR ( or any LBC for that matter) rides, is a GREAT place to be.


One of the Mark's in the great state of North Carolina
Sunny and in the 70's (F) today
Mark Riddle

Don & Mark--Jim is referring to the solenoid switch at the O/D, not the column switch. On the column, it's reversed: DOWN is ON and UP is OFF (at least on mine). I believe this to be the best arrangement to prevent inadvertant engagements (not my daughter);)

Rick O.

Rick Orthen

You are absolutely correct, Jim's question was about the lever on the OD itself. I was merely commenting on the Switch on the steering column, that in some intances operates in reverse of what was originally intended by the factory install.
I am sorry if I did not make that clear.

On the desired position of the column switch, as you have pointed out, I have to agree with you. Once I got used to UP=OD off and DOWN=OD on, as my "conversion" switch was supplied, there seems to be less opportunity for "nadvertant"engagement of the OD.


Mark Riddle
Mark Riddle

my 75 is up for off and down for on. I beleive that it was up for off because it is out of way of the turn signals and you only use OD when cruising

Rick O
I think this time Jim is refereing to the switch (on/off) at the steering column. Jim refers to the lever at the OD as a LEVER. Now that we are totally confused....:)
My OD switch is as Don E puts it...which is the
"conventional" way of thinking, up is on.
My OD switch has only 2 wires, a black and yellow. This is know as a single pole switch. This is the standard configuration for a TR OD switch. Simply, it is either on or off...closed circuit or open circuit. For this one to operate in the oposite way, you must desolder the 2 wires and reverse them. In my opinion, not a good idea. The plastic base the solder terminals are is subject to melt down and the price I paid for the switch says to me do not do this. Who really cares up-on/down-off...up-off/down-on as long as the operator knows which position is ON. I do not think you will loose browny points at a concours.

A switch that has 3 wires on it is refered to dual pole switch. Simply a center common wire and either other wire can be used as the on position (up or down). With this type of switch there is no need to desolder any connection at all. Simple reverse the 2 wires. You must ohm it out to first determine which wire is common to either position then pick the wire that gives you ON (closed circuit...0 ohms) in switch up position...if this is what you want. The left over wire can be cut off and taped.
Mark R, I am currious, where did you get your 3 wired switch from? The one I bought ( 4 years ago) is the correct 2 wire switch.
Rick C
Rick Crawford

RC is prezactly right. THIS time I'm referring to the lever on the column that activates the OD electrical circuit.

Up is on. Down is on. Either works, Up is on is factory.

The goose doesn't care, he flys either way, upside down or rightside up. Ever see an inverted goose? It's not a pretty thing.

Btw, the goose is BACK.

Jim Deatsch

The column switch supplied to me is an original Lucas switch. It is configured as an ON-OFF switch. It has two wires that terminate at the switch itself. But, at least on the switch that I posess, I cannot speak for your switch, it has three terminals only two of which are utilized. This is known as a single pole form "C" contact in my profession. I am a reliability Testing Eng. for CII Technologies, going on 16 years now.
A form "C" type contact has a common point, the center terminal on the switch, that is "connected" to on or the other of the "stationary" contacts depending on the position of the lever. As Lucas is only using only the "common" and one of the "stationary" contacts, the swtch operates as a on-off switch, by completeing the circuit between the two wires that terminate at it, or breaking the circuit if the other position is selected.
On the switch I have, this can be changed merely by taking the outer terminal it is currently located at, and placing it on the unused outer terminal. Thus reversing the function of the lever position. The off position would now be on, and the on position becomes off.
I agree that it is not for the faint of heart to attempt. as soldering on the switch requires great care in order not to damage it. And I myself would not attempt it unless I was very sure of my soldering skills. It also helps that I have access to some very great tools for just this purpose.
Reversal of the wire positions on the terminals will not change the way that the switch functions in the circuit.
Let me apologize if I have in any way offended, I was only offering my experience with the switch that I received.
I will now humbly bow out of this conversation, as I sense we have strayed from Jim's original query.
I hope that the answer has been gleaned somewhere in this thread.
Thank you for your patience,

Mark Riddle
Mark Riddle

Hey Mark,

like the rest, your input is ALWAYS appreciated. I, for one, learn something new EVERY SINGLE day on this BBS and thank all of you who put up with my questions and querys.

I'll leave the OD issue for another weekend and will drive the damn car and enjoy it. <G>


Jim Deatsch

Mark R et al
Obviously, clarification in what one says is the order of this thread.
Jim has been very patient with us all. In his very first post to this thread he says " When the lever on the od unit is up or down?" I noticed, that was what he said and refering to. Unfortunately I stupidly refered to it as a "switch" at the very begining of my post but then said lever from then on. Ron caught it.

Then it got more interesting (Jim you gotta be laughing your head off:) but you caused it.
Jim then says:"Everything I'm finding now indicates the switch should be in the UP position to be in OverDrive." ( I am thinking and posted Jim is now refereing to the column switch) Now posters are talking about the OD lever....I am starting to laugh now:) Jim...please... no more 180* turns anymore:) Steve also saw Jims 180* turn:)

Mark R. I Quote you:
"There are three terminals where the wires connect to it. One is common, and the other two are "operational" in one or the other of the switch positions."
I took this to read that you "physically" have 3 wires attached to your switch (" where did you get your 3 wired switch from?") . I humbly say I went out and had a closer look at mine. 2 wires Black and Yellow/green....I twisted the wire over and saw the green tracer. I am positive we have exactly the same switch. You are correct, there IS 3 terminal points. Only 2 have wires on them and yes if one of the wires, Black, was moved to the empty 3rd position the switch would operate in the oposite way. Being a self employed lowly Electronics Technologist for over 16 years, I missed (in my first obsevation)the blank 3rd terminal on the Single pole switch. Now there is my mistake. I suppose I was looking more for having 2 wires attached as compared to 3 wires, I was not looking for a 3rd terminal. Where I come from this would be refered to as a SPST.... ON-OFF. Now that I have opened up my bad eye:) I do see the 3 terminals which is a SPST... ON-ON.

Yes Mark we agree...the removal and solder to the other terminal is not my first choice.

OK Jim, lets get back to your "switchin lever" NUK NUK

Mark R. do me one small favour please. Since we have multiple same name people here would you please say which Rick you are refering to. Thank you. Also no offense intended here.
Rick C
Rick Crawford

The 15 Stooges. We should take it on the road. <G>

You guys quack me up.

Jim Deatsch

I am about to buy a TR6 at the moment its a basket case but the body seems good the present owner claims it has overdrive the gearbox is still in the car the engine is in the trunk of a 48 pontiac how can i tell wether or not it really does have overdrive the car really is a project car.
Thnks Peter
Peter Fryer

2 ways. Are there 2 levers on the left side of the steering column. One is turn the other (closer to the dash) is the OD switch.
If the interiour tranny cover is off you will see either of 2 things. If OD you will see an attachment (the OD)to back of bell housing (clutch) then a short tail stock to the prop shaft. If no OD then a long tail stock from bell housing to the prop shaft. You can always look under the car for this. If it has OD there will be a very large (2"??) brass drain plug on the bottom of the OD.
Rick C
Rick Crawford

This thread was discussed between 14/04/2004 and 25/04/2004

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