Overdrive connections

[deano]

Has someone photos of the top part of the gearbox showing where the spade connectors fit. It's a struggle to locate them.! I would like to meet the fool that put the gearbox back without re connecting them

[Jon Tilson]

No pics but it works like this.

Green feed to reverse light switch and back to loom connector near bell housing.
Parallel green feed to o-d inhibitor switchm which should only conduct in 3rd and top.
Switch out to stick swithc loom connector.
Stick loom goes up to switch and back down and out to loom bullet connector.
Bullet loom connector to o-d solenoid.

O-d solenoid has an out to earth.

Hope that makes sense.

Jonners

[deano]

Right I'll have another look tomorrow, bathroom has to take priority.. It's difficult to see the connections on top of gearbox with minimal room.
Thanks ,I'll get to it this week

[deano]

Well, firstly the good news....

I reconnected the wires and hey presto it worked. Happy days I thought until the engine n box were warm n then then it stopped engaging

On cold engine it engaged very quickly with no problems. The oil in the gearbox has been topped up with quality synthetic gear oil. I was thinking as everything warms up there may be a loss of pressure but even so there is a slight leak not enough to suggest loosing pressure from a leak.
I should check the pressure as suggested by mr Haynes. Does anyone know what size type of threads the connections are?

Any ideas!

On another note the car is running great so well in fact think I need an LSD

[Toledo Man]

The synthetic oil might have something to do with it...

You should be using normal gearbox oil with NO additives as the additives can wreck the overdrive.

[cliftyhanger]

Triumph specified ep 80 or 90 but gl4 spec. I know laycock spec engine oil, but ep is needed for the gears. I would seriously hesitate to use engine oil in my gearbox.

Anyway, temp causing problems? My guess would be the inhibitor switch. Get a voltage tester out and have a check.

[Richard the old one]

I have also had the problem which was caused by the inhibit switch not making a contact when it got warm.

[deano]

Yeah been told that from someone else too, which makes sense. Didn't realise there was an oil temp sensor ! thanks
Any idea on price. The oil I topped up the gearbox with is GL5 for 75, 80 or 90 older spec equivalent grade so it says on the label. My thoughts are that though a semi synth oil shouldn't effect seals etc as it's not like a motorbike if has a wet clutch only mineral or semi synth due to oil properties effecting the operation of the part

[Richard the old one]

The inhibit switch is there to stop O/D being engaged when the gearbox is in either 1st or Second gear. It is the switch that is situated on the top front end of the gearbox and is not a temperature cut out.

[cliftyhanger]

As to oil spec, if only topped up you may well be fine, but more than that I would drain and refill with the correct GL4 spec.
reason....some GL5 spec oils have additives that can attack yellow metals. As found in gearboxes. Plus have heard it may contribute to overdrive slip. (the cone clutch is in the oil)

As to the inhibitor switch, it is there to only let the od operate in 3rd and 4th gear. Put an od into reverse and it is game over.....

the switch may need a washer adding/removing or something to get it to work correctly.

[deano]

As it's more or less on top of the gearbox what size spanner/ socket is needed to remove it. Washers to remove or add! Should there be one or more already on there as it does work so it is guess work?

Dean

[Jon Tilson]

I tend to undo these with water pump pliers or an adjustable. They have rounded corners and shouldnt be done up that tight.
They are the same as some reversing light switches...just a straight sprung ball pres for continuity.

They dont often give trouble....usually just the contacts on the top work loose.

Bit of a mare to change in situ on a Sprint with the tunnel in place.

Jonners

[deano]

Thanks Jonners.

Do you think it could be this switch causing it not to engage when the engine n box is warm. Couldn't see these switches on rimmers site. Where else can I buy one

[X-pat]

Thanks Jonners.

Do you think it could be this switch causing it not to engage when the engine n box is warm. Couldn't see these switches on rimmers site. Where else can I buy one

I bought mine from Sportscar Supplies via Ebay here:

http://www.ebay.co.uk/itm/INHIBITOR-SWI ... 3ce90e7945

- but I think when I bought them they were cheaper than what is listed now. Rimmers also have them:

http://www.rimmerbros.co.uk/Item--i-BAU1074A

Most of the other usual suppliers will stock them too, I suspect.

[deano]

Thanks, one ordered from rimmer bros.
I'll get to it later this week. Car passed MOT though brakes sticking on!