O/D help

[Tryumf]

I have a problem with a 3 rail box with D type overdrive, have bought this and it was claimed to be working before being laid up for quite a while (about 5 years or longer). Have replaced oil, checked solenoid and lever setting and all seems ok but still getting nothing but a distinct click when trying to engage overdrive - any suggestions on what else I can try without doing a major strip down...David

[monty69]

I know it a different car but I have been play with a MG that has been of the road since 2002 it pasted the mot with a few bit.

BUT no overdrive, I tracked it down to a broken wire in the gear stick and the switch.

So I did a temporary repair with a switch mount on the dash but still no over just a click.

Any did the oil change and cleaned the filter and changed the O ring on the plunger
Still no overdrive, well I went for a long drive today up to Borth and coming back I flicked the switch and the overdrive started to work.

Not saying that your will but it may be worth a try.

[Dale]

Assuming that the click is coming from the solenoid (not just the relay) and that the arm is moving OK it is possible that the operating valve or pressure relief valve inside the unit is stuck.

Try tapping the biggish brass nuts on the unit sharply but not too hard with a hammer whilst operating the switch and see if that does it, if not you're going to have to start taking things apart in which case get a decent manual or get someone else to do it for you.

[Tryumf]

All the electrics have been renewed, I went out for the first time last weekend since fitting the gearbox and I tried switching it in and out but nothing happend.

[Tryumf]

Is the middle nut the one with the valve in

[Dale]

Are you sure that the click is coming from the solenoid?

[Dale]

Just trying to remember, been a while since I've played with a D type, might be the one on the right hand side.

[Pete Lewis]

can you get an ammeter in the solenoid feed wire if its opereating and the lever is set OK
it should pull about 10 amp for a short second and hold in at about 0.5 amps
if you feel the solenoid you should feel it kick and with the side cover removed see the valve lifting lever move rearwards
this lever lifts the valve pin to let oil pressure thro'
take the cap screw  off the top of the box and see that the pin and spring lift a small amout freely the valve pin has a small hole in it which must be clear
if levers are worn you can add 1/2 turn on the solenoid rod nut to lift the pin a small amount more than the line the holes will give
but check you have a 12v feed to the solenoid first
the 2 current consumptions are due to the pull in coil takes a hi current then when core is at the end of its stroke there is ahidden  switch in end of the solenoid which cuts in a lower consumption coil and disconnects the Hi one    
Pete

[Tryumf]

Thanks for all your previous replies,

I have checked the opperation of the solenoid and opperating valve but still no luck so now its an overdrive out job.

Is it possible for me to remove the overdrive unit without removing the full gearbox and if so how much lift would be required.

Should I have a go at repairing it myself, I feel I am a competent mechanic although I have never done anything like this before or should I just go for an exchange unit, I would hate to think I had spent £300 or so if the my old unit needed a new o-ring or something was just sticking.,,..any suggestions..David

[Deleted User]

Technically, you might be able to tilt the gearbox up enough to remove the overdrive with the garebox in the car, but WHY ?

You will already have removed most of the interior to get to the gearbox, so why not just remove the gearbox complete, it will probably be easier, and less work !

[Tryumf]

KevinR wrote:

Technically, you might be able to tilt the gearbox up enough to remove the overdrive with the gaerbox in the car, but WHY ?

You will already have removed most of the interior to get to the gearbox, so why not just remove the gearbox complete, it will probably be easier, and less work !

Just thought there would be less to take off and not so much lugging about, But as you say Kevin it might be easier to take the whole gearbox out in the end..

[Pete Lewis]

you can take off the od in vitesse but think spitfire has less room to extricate it  
never take of the adaptor plate or the mainshaft will come with it, if you jack the gearbox up high watch for hose stretch and fan fouling.
its more fiddly to realign the one way clutch splines when in the car ,,its hard enough when its on the diningroom table
if you strip it out get a proper manual  TSSC shop do manuals and CD roms   Pete

[Tryumf]

Removed my overdrive unit yesterday and checked out what I could, ordered a recon unit that arrived this morning  and refitted it,

I found it easier to do it without removing the gearbox so saved myself a lot of extra work :) :)..David

[Pete Lewis]

Thats good     Pete