Overdrive

[Gilespfr]

There are some good posts on o/ds not working, which unfortunately is the case with mine, although it does click when the ignition is on in 3rd gear. So is my plan sensible, to check the contacts, then the solenoid and finally gear oil level (this last bit is not well documented - is it tricky).

cheers

Giles

[stag8manod]

Hi Giles, Just filling the level in the main gearbox to the correct level automatically fills the overdrive correctly. Do this first.
Cheers Ian A

[Gilespfr]

Thanks Ian
I'll try that - have you had issues with o/d?
cheers
Giles

[flying farmer]

If you have an A type overdrive there are a set of contacts under the plastic end cover of the solenoid. There are two coils in the solenoid, a high current pull in coil, then a low current holding coil. The contacts feed the high current coil IIRC, I think through a relay. When the contacts corrode you get a click but the overdrive will not engage as the pull in coil is not operated.
This was a regular occurrence on my 71PI saloon during the damp Winter months, and a PITA to clean up with fine wet and dry knowing it would happen again in a few months!
Neil

[trunt]

If all that fails..

I rebuilt an A type for My TR years ago, after adjusting the solenoid the method of adjusting the operating lever is to insert a rod (e.g. drill) through the operating rod and in to a hole in the casing and adjust it to that setpoint when engaged. (see section 40.22.01 of the operations manual) fine if its newish but over the years if the internal linkage wears its may not be enough to make it engage, In my case I adjusted it the surefire way, which is to measure the lift of the ball valve using a dial gauge, fine if its off the car -- but IF NOT try adjusting it so the lever stops a little past the setpoint when its engaged.

Oh.. and If you go too far it will have trouble disengaging..

[stag8manod]

Not really Giles, only the usual wires up the gearlever. Rebuilt the main gearbox 12 months ago, never touched the overdrive as it was fine. One thing I've just thought of is, there is a high pressure oil filter up in the bottom of main OD case which needs to be checked occassionally but needs a pin wrench to access it. I don't think this is any thing to to with your problem just some extra information.
Cheers Ian A

[Gilespfr]

If you have an A type overdrive there are a set of contacts under the plastic end cover of the solenoid. There are two coils in the solenoid, a high current pull in coil, then a low current holding coil. The contacts feed the high current coil IIRC, I think through a relay. When the contacts corrode you get a click but the overdrive will not engage as the pull in coil is not operated.
This was a regular occurrence on my 71PI saloon during the damp Winter months, and a PITA to clean up with fine wet and dry knowing it would happen again in a few months!
Neil

Thanks Neil
A local Stag trend thinks it is a J type!

My jack has lost it's spring so I need to sort that before do the gearbox oil - I am not keen on going via interior!

Cheers

Giles

[Gilespfr]

Thanks Ian

[Marco Polo]

Giles,
There is a shuttle valve with a couple of O rings on it, you will find it when you remove the overdrive solenoid, over time these Orings go hard and prevent the overdrive operating properly. If you replace the Orings as well as checking the oil level, this may be the end of your troubles. I cant help you with a supplier in the UK but Im sure all the usual places will have them.
regards,
Raoul

[TR5convalescent]

Even the tiniest nick in those O rings can affect engagement. Ask me how I know! ��

[Carboy0]

I have used these guys for parts previously.

http://www.overdrive-repairs.co.uk/buy-spares.php

[Gilespfr]

Cheers Raoul
How's Aussie?
Giles

[Gilespfr]

Funny they don't mention Stags?

[susiedeer]

Funny they don't mention Stags?

And they don't mention Bristol and they use a J type

[Marco Polo]

Cheers Raoul
How's Aussie?
Giles

All good here Giles, warming up nicely, clear blue skies and 29C, perfect Stag weather