Overdrive inhibitor switch

[jonnygangsta]

Hi guys,

After checking all the previous posts on a J model overdrive not working, I think I have narrowed it down to the overdrive inhibitor switch. I have been under the car and there is a loose wire with a spade terminal in the area but as you know it is almost impossible to check the switch, without dropping the gearbox.

My question is, can I do this without removing the prop shaft?

For your info, I have changed the gear lever switch, the short wiring loom, and checked the reversing inhibitor switch. The overdrive worked before the car went in for an engine rebuild but this is one of many minor snags it came back with!

I have basic equipment available to me, ramps, trolley jack etc and posses only a basic level of engineering know how! However, I don't lack enthusiasm and I am not afraid of skinned knuckles!

Any information relative to this, will make the weekend coming, so much easier to plan!

Thanks, in advance,

Jon

[Colinh]

Hi Jon
My overdrive stopped working shortly after I bought it, the oil level was a bit low, topped it up and away she went after a couple of try's of the switch.
Well worth a check.
Colin

[richardthestag]

Rom suggests disconnecting negative battery lead, pulling two electrical connectors off the solenoid and using a 1" (25mm) open ended spanner on the hex on the solenoid to remove. Helpfully shows a line drawing of a hand holding a spanner fixed to the solenoid and no missing knuckles or nasty gashes

I recon that both exhaust and gearbox cross member will be in the way. Cross member is 6 nuts, four on the ends of the cross member through the floor and two to secure the cross member to the end of the overdrive unit. Support gearbox on jack and axlestands etc etc etc

What colour is the mystery wire with spade attached that is dangling? The 12v feed looks yellow/purple the other wire could be black for earth i guess

[jonnygangsta]

Colin,

Thanks for your quick reply! I forgot to mention that I checked this also! Oil level was spot on, as I removed the level plug the oil started to seep out. Possibly worth mentioning that the car was parked nose down, on my driveway, which has a very slight nose down gradient! 2 degrees max (ish!)

Jon

[73stagman]

We have changed a switch with out taking the gear box out on Mr Crossmans car once! The transmission tunnel has been "modified" ( crudely) where the gear selector comes through in order to gain access.... then it broke again so we changed it and installed long wire tails whilst we were changing his clutch recently

[jonnygangsta]

Hi Richard,

I seem to remember that the wire was yellow, but at the time I was struggling with the reverse inhibitor switch. Plus the wiring on my Mk 1.5 does not conform to the wiring diagram 100% of the time!

I read a post about removing the support bracket, whilst supporting the rear end of the gearbox with a trolley jack, but I thought this would damage the prop shaft?

Jon

[jonnygangsta]

Neil,

I think I read about the fun you had doing that!

I don't think I am quite ready to cut the transmission tunnel bodywork just yet! Although, that was also suggested in the posts!

Jon

[73stagman]

Neil,



I don't think I am quite ready to cut the transmission tunnel bodywork just yet! !

Jon

Absolutely right!
However putting the long tails on the switch was a great mod! We got them soldered on by our ET guys along with some heat shrink and can now work on the OD wiring with ease.. no more broken terminals as that was what happened to Crossy's switch too... don't think it lasted three months. More due to the awkwardness of getting hands and tools into the tunnel to attach wires and nothing to do with the quality of the switch I must add.

[jonnygangsta]

Neil,

I have 5 meters of thin speaker cable! Trouble is, I still have to address the problem of getting to the switch!

Speaker cable was a joke BTW!

Jon

[tjk]

Hi
I would agree that exhaust pipe and prop would have to removed but cross member can be left attached to gearbox. Just lower gearbox with your trolley jack. Make sure car is high enough off the ground with health and safety in mind ie well supported. You can check switch wiring first by running wire from gear stick switch direct to overdrive but be careful when doing this that you ensure switched off when not in 3rd or 4th as you would damage the overdrive. Also if gearbox is lowered the brake pipe on engine cross member can be crushed by engine swinging up.
Tim

[richardthestag]

What about the cooling pipes to the radiator? Lower the gearbox, raise the front of the engine! I know that it would pivot on the engine mounts but might there be a risk?

Just a thought

[jonnygangsta]

Thank you for all the helpful tips, plus additional things to consider ie exhaust pipes. It seems as though this is a more difficult task than I first thought/ visualised. I presume the exhaust pipes are not easy to separate, I do have a heat gun but still...! The idea of disconnecting the prop shaft was on the limit of my tech/engineering knowledge.

All to replace a wire to a switch....

Jon

[jleyton]

Rom suggests disconnecting negative battery lead, pulling two electrical connectors off the solenoid and using a 1" (25mm) open ended spanner on the hex on the solenoid to remove. Helpfully shows a line drawing of a hand holding a spanner fixed to the solenoid and no missing knuckles or nasty gashes

I recon that both exhaust and gearbox cross member will be in the way. Cross member is 6 nuts, four on the ends of the cross member through the floor and two to secure the cross member to the end of the overdrive unit. Support gearbox on jack and axlestands etc etc etc

What colour is the mystery wire with spade attached that is dangling? The 12v feed looks yellow/purple the other wire could be black for earth i guess

Unless I'm misreading everything (quite likely ) you're referring to removing the overdrive solenoid, whereas the thread is about removing the inhibitor switch

Cheers

Juliuan

[jonnygangsta]

Hi Julian,

I need to access the overdrive inhibitor switch to check if a wire has come off the terminal. Having read previous posts, it would seem that this is nigh on impossible, without dropping the gearbox. I was trying to work out if I could do this with my limited experience?

Thanks,

Jon

[jleyton]

Hi Jon,

Yep, I realised that but I just thought that Richard was referring to the wrong part

Good luck. Cheers

Julian