GT6 MK3 overdrive electrics

[garypowell]

I did read through this section before asking but found nothing to answer my problem. I bought my GT6 after it had been off the road for 8 years and part restored. It has taken me ages to work through what the previous owner either didn't get round to or ran out of patience. It's now on the road and driving fairly well but the overdrive electrics are a bit of a puzzle to me even after looking at many diagrams and workshop manual. My gearbox starting from the bell housing has a switch mounted on the top left hand side looking forwards, then under the gear lever remote there is another switch finally is the solenoid mounted rearward low down. The solenoid was the only thing with any wires going to it apart from the gear lever switch. What I can't suss out is which of the two switches is the OD inhibitor and which is the reverse light switch and how to wire them both correctly. I have a downloaded diagram but I'm struggling. Does anyone have a picture of how theirs is wired to make things really simple for me please?

[Pete Lewis]

The switchnunder the tower is the reverse switch

 

the OD 1st 2nd inhibitor switch is the one mounted on the bracket in front of the remote the romote rod

has a cam which cuts the feed to the solenoid whenmin 1st or 2nd gear.

 

 

the Dtype (solenoid on drivers side) must have a relay to operate the solenoid

there are two coils in the sol. one pulls in at 10amps and then a switch in the sol. cuts in a holding coil at 0.5 amps

 

whether you wire the inhib switch in the solenoid feed or the relay trigger line or the earth is down to

how you like to wire it

 

wires down the gear lever are notorious for chaffing and failing, use silicon wire down the hollow gear lever

a column swith is much less problems.

 

but have a fused battery supply to the relay, and use the g knob sw or column stalk to trigger the relay

 

from a whiite on the ignition circuit.

Pete

[garypowell]

Thanks Pete, to my rescue again. I'm a little confused as to what gearbox and overdrive I have now as my solenoid is on the passenger side. Now I do know from the engine number that it's from a Triumph 2000 so does this mean the gearbox could also be from something other than the GT6 do you think? Now I know at least why the reverse lights were not working and I installed a switch on the dash instead. At least now I know which switch is which I have a starting point thanks.

[Pete Lewis]

, if sol is on near side its J type doent need a relay does need the inhibitor.

 

which way is reverse , left and fwd 3 rail box or right and fwd single rail box

Pete

[garypowell]

Reverse is left and forward Pete, I suppose if it was the original gearbox it should be a D type because the J type was an earlier gearbox on the GT6 if I'm right? So it appears I don't have much original GT6 mechanics. This could become complicated until I learn more about the make up of the car. Thanks again Pete.

[Pete Lewis]

Good its got a 3 rail box ie there are three selector shafts with one fork on each shaft not the single rail

which had all,3 forks on one shaft and the seletor toggled between them , introduced as a common box for marina, s and triumph.... its all similar but not the same components,

 

you can see the 3 shafts sealed with a welch plug in the top cover

[garypowell]

Thanks for your help Pete, I tackled the Overdrive wiring this morning and after another few hours work doing other stuff went for a test drive down a coastal road and overdrive works great in 3rd and 4th. It comes out of 3rd instantly but has a 15-20 second delay coming out of 4th which I don't consider to be a problem. That's one more step done.

[Pete Lewis]

It should react about the same the od doesnt know or care what gear youre in

 

it relies on disengagement on rate of pressure drop, not what gear your are in and the od pump runs on a cam on the mainshaft which is prop speed relative not gear selection relative.

 

Give dave twigger a call at odspares

 

 

http://www.odspares.com/

 

 

if younwant some more ideas