Overdrive gearstick switch mounting

[Martin V]

Please can someone let me know how the gearstick based overdrive switching unit (gear knob ) is attached? I’m trying to look into mine as the switch is always on /earthed currently meaning Overdrive is on. I’m hoping the fault lies in the quite wobbly switch/knob. From the parts book it looks to be threaded but I don’t want to force it and break it.

[Peter Truman]

The gear knob plastic top with gearchange pattern on it just pushes off, there's a small rectangular cut out on its bottom lip where it joins the metal of the actual knob put a thin bladed screwdriver in it and twist, be careful and not ham-fisted, the top then comes off the knob complete with switch you can then remove the two push on electrical connectors & check the switch for operation & connectivity with a multimeter, replacement switch's are available and if you don't mind losing the ON/OFF lettering there are other easily obtained and cheaper generic switch's available, a bit of the wife's red nail varnish for the ON or active position suffices.

Ref the knob left on the gear stalk it should be tight there's a thin nut in the top of the actual knob body which is hard to tighten up just ensure it has enough grip then tighten the chrome tapered nut on the underside of the knob using the two small flats filed into this nut, that should tighten the knob on the stalk.

The two very thin wires that go up the stalk into the knob and push onto the switch can get damaged causing an earthed or active connection but there easily replaced with suitable thin wires reconnecting to good wiring below the gearbox cover (gearbox cover out job) new switch push on connectors are difficult to obtain I've used some Telephone push on connectors soldered on and heat shrunk that were locally available here in Aus.

Hope this helps & others may also expand the knowledge, sorting out the problem is not difficult just needs care. There could also be an issue with the inhibitor switch fitted on the gearbox or other wiring issues, don't select reverse with the overdrive active as this can damage the one way clutch in the overdrive!

[Martin V]

Many thanks Peter, thanks for taking the time to share the knowledge. I’ll look into it more following your tips.

[Pete Lewis]

as the wires down the stick will probably have degraded  if a rewire try to use some silicon sleeved wires that resist the heat much better

the small terminals that connect wires to switch are fussy and often spread so contact becomes unreliable  

needs a small soldering iron to swap them  ...they are quite small and finicky  if you need to give them a squeeze take care   easy to flatten them 

Pete 

[dannyb]

As Peter says, the wiring can be a problem. Over the years of oil, heat and movement it becomes iffy.  If the switch itself needs changing, I have. Have found the replacements to be poor quality and never lasted long. I ended up with an Healey 3000 works type.

The thread is different so the gearlever will need to be re-threaded to match.

[Mjit]

Working up the gearstick from bottom to top you have a chromed, tapered nut with 2 slights flats on it, then the main body of the knob, then a second nut with just cuts into it's top face, then the plastic cap with the switch in it.  What I do is:

1. Pop off the plastic cover as Pete said.
2. Just crack off the bottom chromed nut so the pressure's off.
3. The top nut will also now be loose and you can use a small screwdriver or similar in the slots to spin it off.
4. Once free you can just pull both the top nut and knob body off (body isn't threaded, just slots in groves cut through the threads on the gear stick).

Refitting what I do is:

1. Bottom chromed nut screwed all the way down the stick.
2. Drop on the knob and top screw.
3. Use screwdriver/etc to screw top nut down until it's flush with the top of the gear stick.
4. Screw the bottom, chromed nut back up the stick until you get to the knob, then just a quick nip up of the bottom nut with a spanner to lock everything in place.

[John Hill]

I had this problem on mine a few years ago (Herald with D type O/D)....I was actually getting a shock off of the gear stick, not much fun 😄

I replaced various parts, including the switch....hmmm!!  Although it says 'Lucas' on the box I don't think so somehow.  The new switch was cheap and nasty and actually worse than the one I was replacing.

The upshot is that I did away with the gearstick switch and went with the stalk type found on the Vitesse.

Much more reliable 👍

IMO

[Pete Lewis]

had both  and agree column stalk is hands free , and less trouble 

Pete

 

[johny]

1 hour ago, John Hill said:

I had this problem on mine a few years ago (Herald with D type O/D)....I was actually getting a shock off of the gear stick, not much fun 😄

I replaced various parts, including the switch....hmmm!!  Although it says 'Lucas' on the box I don't think so somehow.  The new switch was cheap and nasty and actually worse than the one I was replacing.

The upshot is that I did away with the gearstick switch and went with the stalk type found on the Vitesse.

Much more reliable 👍

IMO

Agree on the gear knob switch and as the column stalk switch is too much hassle and expense Im going for a long illuminated flick switch mounted under the dash bottom rail for the D type OD conversion on my Vitesse. Reckon I can operate it with minimum time hand off steering wheel, can see if its in or out without taking eyes off road, do away with relay as switch is beefy enough and reduce wiring in the arduous gearbox environment... 

[rlubikey]

I love my overdrive switch on the gear knob!!!

On 25/07/2023 at 08:44, Pete Lewis said:

if a rewire try to use some silicon sleeved wires that resist the heat much better

Yes, don't be tempted to use two core 3A mains cable like a previous owner of mine did. Household cable isn't rated at a high enough temperature for vehicle use and mine melted on a hot summer afternoon back in the noughties!

I used two vehicle rated single core cables but they abraded through eventually. I added a piece of glass-fibre reinforced silicone sleeve from a slow cooker or iron or something else that gets hot. It was slender enough to go through the gear stick but wide enough for the two cables and it's worked perfectly for well over a decade.

Another failure is the connectors inside the gear knob which I think have no insulation. I got some heatshrink tube to cover each one completely, then slit down the side just where the switch contact fits in - much more confidence inspiring.

Martin, I think you must be lucky about your short circuit which must be from wire to wire (overdrive on in 3rd & 4th), instead of from wire to gear stick - hence chassis - which blows the fuse. I think all you loose is your reversing light. Do your symptoms match what I've described?

Cheers, Richard

[Gully]

22 hours ago, rlubikey said:

I love my overdrive switch on the gear knob!!!

Cheers, Richard

Me too!

Gully

[Peter Truman]

Switch in the gear-knob in the gear lever is a Touch of the James Bond Goldfinger Ejector Seat!

I fitted gearknob switch in the daughters  Mk2 J type conversion she prefers it 

[Graham C]

I also go for the switch on the gear level as well, I have managed to repair the switch that is screwed into the lid. It is possible to split the switch to clean it out.

Graham

[Steve P]

The modern offerings from the usual suppliers are rubbish, they last about 20mins before becoming intermittent. At least mine did on the Vitesse.

Going to try and rebuild the old one.

S

[Graham C]

It was the original 1981 BL one on the car.

Graham

[Martin V]

Hi All,

thanks so much for you advice. With tunnel out I found the gear inhibitor switch was causing an earth once 3/4 engaged. The earth even happened with the gearstick button wiring left as an open circuit. Conversely if I shorted out the gearbox inhibitor wiring to give a permanent on position the gearstick switch does switch the solenoid on/off.

Having removed the gearbox switch I see that someone , previous owner or other, has had it apart before as they have crimped the edges back down to hold it closed. Most likely creating an earth! 
 

New Gearbox switch ordered and also replacing gearstick wiring whilst at it.

 

Should be all done.

 

Hopefully found my gear oil leak in the process as I found zero gasket between remote and top of gearbox casing!